What bothers me about the whole thing is not so much the aspect that I also indeed think Crusher would not have gone on about "humanity's ability to love being limited" if Odan had walked in with another male host, it's the fact this show is supposed to be set in the future and that TNG in particular always hits you over the head with "we humans are soooooo much more advanced than we used to be". This clashes rather harshly with Crusher's entire attitude.
What bothers me even more tho is that to me this isn't so much a gay issue first and foremost (although it is, of course), it's a trans issue. Being with someone who can't cope with the fact that that your gender is not the one you "had when you met them" and that you need to be yourself and that this means you might lose the person you love in the process is one of the most heart-wrenching things on an emotional level. In the end it's a choice between being who you really are and losing the person you love or remaining someone you aren't/living a lie but keeping the person you love. And Crusher's flippant way of saying "ugh no thanks" to Odan just REALLY rubs me the wrong way, especially since, like I said, this show is supposed to be set in the future. DS9 had a much, much better scene where the Klingons (the KLINGONS, who aren't really portrayed as folks who seem overly open-minded) are like "oh hi Jadzia" when Dax briefly explains that she's now Jadzia and no longer Curzon. Yes, there is the criticism of this being aliens accepting aliens and no humans are involved, but still. That scene is a far more welcoming one whereas Crusher slamming the door in Odan's face without even wanting to TRY to accept Odan with a female host and then blatantly stating that humanity can't deal with this sort of thing is just... unfortunate for a show set in the future that also constantly claims to be super accepting and enlightened and whatnot.
Yes, I realize that a lot of people in this day and age can't deal with the person they love being trans. That's an unfortunate reality, as much as it saddens me, and while I myself would have no issues with the person I love being trans (I love the person, not the gender), I realize that I can't speak for the rest of humanity on this one. If only Crusher realized the same. I'd be far less bothered if she had said "sorry I know many of my fellow humans are cool with this these days, it's the future, after all, but I'm just not, I can't cope". THAT would have been a statement IMO. Regardless of whether this is a gay or a trans issue or both.