@FooFooFalange
Au contraire, it is directly relevant to whether or not it is reasonable to malign someone because of their discriminating between potential sexual partners on the basis of a given characteristic, in this case protected under equalities legislation.
The point of comparison and analogy in the context of debate or forming one's own opinion is to interrogate one's viewpoint and reasoning in relation to the original issue.
If your conclusions about how to treat someone discriminating on the basis of sex and on the basis of sexual orientation are different, one has to ask oneself on what basis you are treating seemingly similar things differently, why so and if it is reasonable and justified. If not, you acknowledge the need to alter your view.
The reason nobody wants to explain it to me, I suspect, is that there is no good reason for treating them differently in relation to sexual preference.
I suspect what we've come up against is a serious confusion between how people reason and behave in their everyday, civilised life and primal sexual drivers. You are in control of and responsible for the former and can and should be called out of you fall short of the standard of fairness and decency society expects of you. You can amend your logic and behaviour if necessary. You are not in control of the latter - you want what you want and lust after who you lust after; there's no manufacturing that and it doesn't make you any kind of 'ist'. It's primal.
(I am given to understand that not everyone fancies me, which can be for no good reason because I am clearly a treat, but I accept it's not their fault. I'm sure they want to, logically, and would if they could.)
The alternative - that people shouldn't be allowed to discriminate on the basis of sex either, lest they be sexist and homophobic or heterophobic - is itself pretty homophobic in denying people a right to their identity as gay.
There's a longer point to be made, I think, about why people feel comfortable saying "no women in my bed, thanks" and not "no black people in my bed" or "no bisexual people in my bed" based on the histories of different civil rights movements but perhaps I'll save that for my next sermon.