Scriptures always ask to act as per Dharma and cause minimum harm to others even in thoughts. If we disrespect other religions or hurt their beliefs, its Adharma.
For Virtue and Sin do not go about and say, 'Here we are'; nor do gods, Gāndharvas, or Manes say to men, 'This is Dharma, that is
Adharma.' But that is Dharma, the practice of which the noble ones
praise; what they blame, is Adharma. (Apastamba 1.7.20.6-7)
The Eternal Duty towards all creatures is the absence of malevolence
towards them in thought, deed or word, and to practice compassion
and charity towards them. (MB Vana 297.35)
In act, mind and speech he shall carefully do what is right; and he
shall not do what is right if it happens to he such as is not
conducive to heaven, or disapproved by the people.(Yajnavalkya
1.156)
Brihaspati says ”That man who practices the religion of universal
compassion achieves his highest good . One should never do that to
another, which one regards as injurious to one’s own self. This, in
brief, is the rule of righteousness.”(MB Anu CXIII)
What is ultimately good for the welfare of all beings is what I
consider as Truth(MB Shanti 329.13).
Since disrespecting and insulting religious sentiments of other religions causes unhappiness to others, it is Adharma. There are many statements in the Scripturas which say all religions including all Non Vedic lead to same truth because its made by Omniscient being. Hence we must to avoid Adharma of disrespecting other religions. Few of such verses which say all Non Vedic lead to same truth are :-
All Vedic and Non Vedic Shastras and many more Sastras, the Omniscient
Divine Being has made in brief.The wise say that each of these sastras
is intended for a particular class according to the individual
qualification, not all for one. As all streams ultimately empty
themselves into the ocean, so all these paths ultimately lead to the
Mahesvara Himself. Worshipped in what form so ever by people as
ordained in their respective scriptures. He assumes that form and
takes the devotee on to the next higher step, By His Grace man attains
to superior paths. Thus these paths, laid out as they are by Shiva,
are all of them true and serviceable. Shiva is supremely merciful,
omniscient, and altogether stainless. Yet of all the paths, the path
of the Veda is the best as conducing to all good." (Chapter 22, Yajna
Vaibhava Khanda, Suta Samhita, Skanda Purana )