* Person A is male and has a wife.
* Person B is female and has a wife.
If you fire person B because of her sexual orientation, you are treating her differently then person A, when the only difference is her sex.I think the dissent does a good job showing the flaws in that argument, but it's better then you're giving it credit for. The flaw is that you could ask on a hiring form:
Are you [ ] homosexual [ ] heterosexual [ ] other.
If they answer homosexual and you fail to hire them, you don't even know their sex - so you can't possibly be treating men and women differently.