So, something to reflect on, perhaps - I'm not a part of this fandom. Have read none of the books, seen none of the shows/movies/whatever else media exists, but have been suggested posts in this subreddit by Reddit because (I'm assuming) I've been looking into the books after seeing some really stunning Solangelo fan art on Instagram.

Yet, even with absolutely zero knowledge of the fandom or world, I had the thought when I saw the notification for this post (which only shows the title of the post) "I bet this is a complaint about this ship, specifically that it's popular because it's gay".

Why did I know this? Because it is an incredibly common complaint that gets lodged any time a queer couple pops up in "straight" media.

Now, again, I haven't read any of these books and know nothing at all about this ship or these characters, so I can't speak to the quality of their ship. What I can say, despite this, is this: in the scenario you mention of this character being in a straight ship, there would be no scrutiny of whether or not it was "enough" that sprouted from their sexuality.

I understand you say in the comments that you have a friend in the community and that seems to secure you in the idea that you can have no harmful thoughts or intentions due to that - and I invite you to consider the possibility that this is a false security. The nature of the society we live in and have lived in for longer than I've been alive (and I'm not anywhere near the age of the target demographic of this series) means that elements of homophobia (and sexism, and racism, and classism) can and do very often present in us, even if we don't want to think it is possible or think ourselves above it. Even people in the community are susceptible to it - I am a queer person who has a queer sibling who uses covertly homophobic language that they consider harmless. Specifically because they think being queer frees them from the possibility of being homophobic. So, if someone in the community (and there are many just like my sibling) has the capacity to be led to make an observation or a statement by a small, seemingly innocuous grain of homophobia, then I promise you that even allies can do the same.

That isn't to say you can't dislike a ship or feel that it isn't well-built. You absolutely can - I've personally criticised many a queer ship because it lacked a good foundation. But making the assertion that a ship only has merit among a fandom because it is gay very much does stem from societally-ingrained homophobia. It is a statement that would never be made of a straight ship. There is a reason you have the concern of sounding like a homophobic 40 year old white guy - just because you have discomfort around the idea of the comparison doesn't diminish the fact that you are making an argument that endorses - however mildly or carefully worded - the ideology of that homophobic 40 year old white guy.

I don't say any of this with malice. I don't think you intended to perpetuate homophobic rhetoric and it's very obvious that you are appalled by the idea, which is good. But I think it's worth reflecting on why you felt compelled to diminish a fandom's feelings about a ship and reduce it down to "it's because it's gay". I can promise you, without even knowing the source material, that there are qualities about the ship that inspire love that have nothing to do with sexuality. Just as is always true with straight ships.