I think you have misunderstood the verses in question and have taken them out of context. It is important to read the first verse of this section 4 and the commentary. The Brhadaranyaka Upanishad with the Commentary of Sankaracarya reads (Swami Madhavananda translator):
VI.iv.1 The earth is the essence of all these beings, water the essence of the earth, herbs of water, flowers of herbs, fruits of flowers, man of fruits, and the seed of man.
The present section is introduced to lay down the method by which to obtain the kind of son who, by the manner of his birth and conception and by his good qualities, will help to achieve the worlds both for himself and for his father. Only a person who knows the meditation on the vital force and has performed the ceremony of the Mantha leading to prosperity, is entitled to this ceremony of the Mantha leading to the birth of a son. When a man wants to perform this ceremony, he should, after performing the former ceremony, wait for the right time of his wife....
and the commentary at the end of the 6th verse says "...therefore he should approach this handsome woman [his wife] and speak to her, when she has taken a bath after three nights."
and the 7th verse says:
- If she is not willing, he should buy her over; and if she is still unyielding, he should strike her with a stick or with the hand and proceed, uttering the following Mantra, 'I take away your reputation,' etc. She is then actually discredited.
...'I take away your reputation,'etc. As a result of that curse, she comes to be known as barren and unfortunate, and is then actually discredited
- If she is willing, he should proceed, uttering the following Mantra: 'I transmit reputation into you,' and they both become reputed.
First, it is sruti. Second, it does not condone wife beating. It says any hitting [and the strikes can be ceremonial, not literally] are only done after several prerequisites. First, they are married. Second, the husband knows the meditation on the vital force [not easy or accomplished by many]. Third, he has performed the Mantha ceremony. Fourth, she has bathed for three nights. Fifth, if after the husband has gone through all these prerequisites and being his wife she is unyielding, he should win her over with gifts. Not yielding, the strikes essentially are a form of renouncing the wife. The purpose of marriage is progeny. If a man has purified himself through all the steps mentioned above to have worthy progeny, and the wife is unwilling to help in the purpose of marriage, she should be renounced.