God sanctions marrying more than one wife. Why do pastors and bishops of churches today tell their women it is wrong?

God Sanctions marrying more than one wife, Infact God has a commandment for men who have more than one wife

Deuteronomy 21:15
If a man have two wives, one beloved, and another hated, and they have born him children, both the beloved and the hated; and if the firstborn son be hers that was hated:
16: Then it shall be, when he maketh his sons to inherit that which he hath, that he may not make the son of the beloved firstborn before the son of the hated, which is indeed the firstborn:
17: But he shall acknowledge the son of the hated for the firstborn, by giving him a double portion of all that he hath: for he is the beginning of his strength; the right of the firstborn is his.

This passage proves that Abraham did not offer Isaac for sacrifice. The truth is that Abraham offered Ishmael for sacrifice and God provided a lamb for him instead.

Now God sanctions marrying more than one wife. Indeed the nation of Israel is built from the children of the FOUR WIVES OF ONE MAN.
The 12 Tribes of Israel are the twelve children of the four wives of one man

Let the truth be told. I know the truth is bitter but God loves those men who have more than one wife and who have relationships with more than one woman.