Well, it's not like I care about playing as a lesbian in every single game there is (that's a common misunderstanding when this topic is brought up), usually it's either:
a) immersive non-linear rpgs, with a player insert character, where romance is either a huge part of the game and/or there's unlockable content gated behind your character being into someone of the opposite sex.
b) most kinds of dating or romance simulators (although ofc there's exceptions, like parodies such as Hatoful boyfriend and I would consider serious games with great story as well)
c) games with a lot of sexual content, kinda, tbh I'm not sure if should count this since I do enjoy games like Catherine. I guess this one depends a lot on tone and context. And it's probably understandable that some kinds of sexual content is an absolute deal-breaker. Like I will never touch "Ladykiller in a bind" (even if looks hilariously bad to make fun of) because it was promoted as a lesbian game with only consensual sex, despite portraying a man raping a woman to "turn her straight" as "successful" and "sexy".
(Fun fact: I managed to avoid buying the game and seeing the (hidden, unskippable) rape scene, because the art's so bad I didn't realise the characters were supposed to be women)
I probably don't have to explain why some games in the last category are unappealing to me. As for the first two, they're just not fun (most of the time) to me if I have to play as a heterosexual. Maybe it's not fun because of the homophobia I have to deal with in real life (with is not insignificant thanks to queer-activists joining ranks with old-school homophobes in trying to force lesbians to like dick), maybe it's because of personal unpleasant experiences or something else.
I'm not really sure why and I don't think it really matters, because it doesn't change the fact that it's just not fun for me. So it simply doesn't make sense to spend my limited time and money on games were I'm forced to play a straight character in way that hinders my enjoyment of the game.
And in escapism, romance and/or role playing games that are specifically centered around freedom and player choice I think it's reasonable to ask for things like same-sex romance options. Doesn't mean all games need to have to them or that it's okay demand it from developers in rude or inappropriate ways. But I think it's okay to ask for (politely! please stop with twitter harassment and shit -.- ) and then buy the games that choose to cater to my demographic.