It would but it doesn't. Jews by and large don't care about homosexual marriage and even find it acceptable per God's teachings. The only ones who don't are the conservative Jews.

Christians on the other hand by and large care about homosexuality alot. Add to it Christians (in the states at least) like to say that they defined marriage, there's proof that isn't true. So if Christians didn't invent it and were born of Judaism that would say to be that Christian belief regarding marriage is irrelevant from a "we created it" standpoint.

Tying it back to my original thought, pointing that out to Christians pisses them off.

This also works with abortion. Most Jews don't care about it, some even go so far as to say this "a baby before birth is merely a part of the mother's body." Meaning it's up to the mother what to do about her body. Up to and including termination.