It's true that the scriptures indeed prescribe principles, ideologies and ways of life which are pro-male. But it's based on physical & mental attributes associated with male-female body & mind.
In other context, during Anushasana Parva, Bhishma also described women in highest regard:
Respect, kind treatment, and everything else that is agreeable, should all be given unto the maiden whose hand is taken in marriage. Her sire and brothers and father-in-law and husband's brothers should show her every respect and adorn her with ornaments, if they be desirous of reaping benefits, for such conduct on their part always leads to considerable happiness and advantage. If the wife does not like her husband or fails to gladden him, from such dislike and absence of joy, the husband can never have issue for increasing his race. Women, O king, should always be worshipped and treated with affection. There where women are treated with respect, the very deities are said to be filled with joy. There where women are not worshipped, all acts become fruitless. If the women of a family, in consequence of the treatment they receive, grieve and shed tears, that family soon becomes extinct. Those houses that are cursed by women meet with destruction and ruin as if scorched by some Atharvan rite. Such houses lose their splendour.
According to Vedic scriptures, it's believed by saints that Women cannot be happy on their own. This should be the reason, why Bhisma discussed certain rules, which are apparently seems little hard in today's time.
There is the well-known declaration of the scriptures that women are incompetent to enjoy freedom at any period of their life. If this were not the path trodden by the righteous, how could this scriptural declaration exist? ... In childhood, the sire protects her. The husband protects her in youth. When she becomes old, her sons, protect her. At no period of her life does woman deserve to be free.
Since you are asking about "how to defend/refute"; Your answer depends on the "predominant" quality (Guna) of the audience.
Answer to Tamasic (Mithyachari, Ignorant, Argumentative)
They might have come across male chauvinism & women suppression somewhere (media, magazine, TV, movies, friends) and just based on their gut feeling, be it right or wrong, they will make some non-sense arguments with you. If you too argue with patience for a while, you can see their voice raising, anger, frustration, making faces, jokes, making fun in front/behind you. Answer to such people (don't lie but just avoid them):
"hmmm .. even Krishna also says in Gita that women are of lower birth. Isn't it strange?"
Nevertheless, if you are successful in convincing them sweetly, then those may become your followers!
Answer to Rajasic (Dambhi, Passionate, Debater)
Such people consider, "winning a habit" or "success a journey". They are not foolish or senseless but often well versed with their convenient knowledge. They may not open their horizon if not treated in certain way and would find ways to prove their point to win over you for their pride.
Though they hardly surrender, if they are helplessly proven wrong, then they might end up hurting you or even create a propaganda. Since they are intelligent (not enlightened), it's your duty not to misguide them just to serve their ego, yet be very brief. Answer to such people:
"Rama, Krishna, Bhishma said such pro-male ideologies in a time when there were no female foeticides, no wife beatings, no restrictions from social interactions, no honor killings, no dowry harassments. Hence their view was neutral and eternal. If you feel that either they or their teachings were non-sense, then better to leave the discussion here.
If ideology of unequal rights to male/female is wrong according to some people's opinions, then it's a stalemate or deadlock of their trust."
Depending on their readiness, you may also disclose some of the details from below, but be careful. You may end up inviting more trouble while fixing one. First you have to explain Varna Vyavastha, but then the anti-caste people will be hurt. When you explain the real definitions of 4 Varnas, then the so called higher castes (just due to surnames) would be hurt. All these troubles also don't guarantee that your male-female differentiation would be accepted. :-)
Answer to Sattvik (Sthitapragya, Calm, Knowledge seeker)
Stree(woman) = Shakti(power)
Women forms are integral part of Vedic culture. They are prayed in form of Shakti, which is evident as their association with many deities. Shakti/Stree has right to choose their responsible Swami (Swayam-Vara). Swa-dharma of Shakti/Stree is to get molded & acts in accordance of its Swami(master). That's why a wife is called Ardhaangini (half body of husband). She acts as of her husband commands to his own self.
Due to moldable nature, due importance is given of securing women. Arjuna feared that post Mahabharata, if women of all warriors get polluted (i.e. marrying to anyone due to lack of men), then the whole society will be vanished.
Wise man doesn't give controls to the Rajo Guna, which usually prevails in women.
Like "power", women naturally have a nature of attachment. Various attachments are associated with Rajas. It supposedly increases during MC, hence it's called Rajaswala. Draupadi was dragged by Dushasana during her this period and she remained so attached to the destruction of the Kauravas, that before Krishna's final peace negotiation, she asked "What will happen to her insult, should the Kauravas agree for peace?!"
Hence, among 3 Gunas, Rajas is the one which must be consciously controlled.
Some may ask, why women are compared with Shudras (as of it's insulting). We should remember that a soul/jiva holding certain body is independent of gender & division. According to Karma, it has acquired certain type of material nature constituting certain division and gender. Similar traits of moldable nature and surrendership are defined for Shudras too.
Shudras are not so called lower castes, but they are just "trainees" in any given fields. In today's hybrid time, we associate the divisions with surnames or body characteristics, i.e. Brahmin, Kshatriya, Vaisya, Shudra; or even Stree, Purusha. Which is not correct. It should be done with respect to tendency/Swabhaav and duty/Dharma; i.e. Swa-Dharma.
In a society, Brahmins will be least in numbers, little more will be Kshatriyas, many more will be Vaisyas and most will be Shudras. Especially in today's time, all those who do job and earn money for well being can be considered Shudras (ignore their surnames). A Shudra trained under Brahmin/Kshatriya/Vaisya becomes Brahmin/Kshatriya/Vaisya after perseverance (call it Yajna). This 4 Varnas are eternal and are not limited to India but all human societies Similarly a woman married to the man of X division becomes X herself.
After reading above, if we refer to what Bhishma says in Anushasana Parva, it's easily understandable that mother goddess who is Shakti will not reside in those women who are not acting according to Lakshmi's (Stree) own Swa-Dharma which is surrendering to Swami. It's so trivial!
Answer to Atman (Brahman, inner self, soul)
References (taken from vedabase.com; need better translation)
 BG 9.32 — O son of Pṛthā,
those who take shelter in Me, though they be of lower birth – women,
vaiśyas [merchants] and śūdras [workers] – can attain the supreme
 BG 4.13 — According to
the three modes of material nature and the work associated with them,
the four divisions of human society are created by Me. And although I
am the creator of this system, you should know that I am yet the
nondoer, being unchangeable.
 BG 1.40, 1.41, 1.42 — When
irreligion is prominent in the family, O Kṛṣṇa, the women of the
family become polluted, and from the degradation of womanhood, O
descendant of Vṛṣṇi, comes unwanted progeny. — An increase of unwanted
population certainly causes hellish life both for the family and for
those who destroy the family tradition. The ancestors of such corrupt
families fall down, because the performances for offering them food
and water are entirely stopped. — By the evil deeds of those who
destroy the family tradition and thus give rise to unwanted children,
all kinds of community projects and family welfare activities are
 BG 3.37 — The Supreme
Personality of Godhead said: It is lust only, Arjuna, which is born of
contact with the material mode of passion and later transformed into
wrath, and which is the all-devouring sinful enemy of this world.
 BG 18.44 — Farming,
cow protection and business are the natural work for the vaiśyas, and
for the śūdras there are labor and service to others.
 BG 18.42 —
Peacefulness, self-control, austerity, purity, tolerance, honesty,
knowledge, wisdom and religiousness – these are the natural qualities
by which the brāhmaṇas work.
 BG 18.43 — Heroism,
power, determination, resourcefulness, courage in battle, generosity
and leadership are the natural qualities of work for the
 BG 18.41 — Brāhmaṇas,
kṣatriyas, vaiśyas and śūdras are distinguished by the qualities born
of their own natures in accordance with the material modes, O
chastiser of the enemy.
Silence is the true & perfect upadesa.