It was a common position in Christianity at certain points in this nation's history that black people should have less rights than white people. Literally the Southern Baptist Convention came into existence because the northern Baptists were too anti-slavery. "But religion" doesn't let you separate distinctions on sexual orientation from distinctions on race.

(Disclosure, I'm Christian, but also I'm a non-white member of the whitest mainline Protestant denomination in the US....)

And it was Christianity that you can thank for the abolition movement.

The literal definition of an analogy is that it uses a different scenario. That's not what false analogy means.