@slothArmy

I don't have Homestuck pages handy, but there are MULTIPLE moments Dirk's sexuality is brought up and made a key point of the story.

His conundrum with regards to how choosing Jake denies Jane a romantic partner.

His conundrum with how being gay denies Roxy a romantic partner. That elaboration comes later, our first interaction comes at the hands of Roxy pushing Dirk to discuss the idea of them dating, despite how uncomfortable it makes Dirk, but Dirk is also reluctant to say that he's gay because once again he'd rather provide the false image that SOMETHING could happen with Roxy, than outright say "no, leave me alone."

His issues with how HAL will flaunt erotic roleplay in his face, because HAL doesn't care in the way Dirk does. (Or perhaps HAL is a version of Dirk who isn't 100% figured out on his sexuality, it's not entirely clear, but either way it's used to taunt Dirk about something Dirk will never do.)

The whole trickster climax is Roxy forcing Dirk into a kiss, after Jake comes around and talks about how great it would be for them all to have babies together. Roxy literally tries to force a ring on Dirk's finger.

His eventual discussion with Dave, on the rooftop, which as I said culminates in the advice re: coming out.

Multiple moments of the story feature the irony that Dirk is kissing women, something which the story draws attention to by censoring the moment it happens (to also build up the climax of Dirk and Jake kissing.)

Obviously there are other elements to Dirk's character and story, but being gay is directly woven as one of the main ones.