I don't know if I made sense at all but my main crux is that being gay (for Dirk) and being attracted to men (for Dave) became key parts of their characters arcs and identities. Moreso for Dirk, since his whole self loathing stems from that "original sin" so to speak. And I think that the moment you, as an author, decide to tackle something that heavy, you have a duty to your readership to treat that with respect.

I think similarly for any type of marginalized identity that gets explored in media. If you're going to make a part of someone's marginalized identity a key character point, you can't then turn around and make that character as the most bigoted depiction of their identity. I think it's careless and in this case, I land thoroughly on homophobic. I do feel that there is an element of homophobia STILL present in how Homestuck is written, though the new team that's currently at the mantle is obviously trying to veer away from the pre-written ideas; it's just a shame they're stuck with what came before.