Hagar was taken because of doubt that Sarah could conceive. It was sin. With Jacob, he was tricked into marrying the oldest daughter first. That was sin. Then the giving of the handmaids was about competition and jealousy. Also sin. The polygamy in the OT was not God’s design. It does not seem that heterosexual polygamy was as offensive as homosexuality. It was not God’s design, but it did not bring the wrath that the other brought.
I agree with you. :)