it was confirmed by hussie on several occasions in a tweet, in a vine and by others who have worked with him on homestuck on reddit and twitter
dave isn’t STRAIGHT. he’s talked to Dirk about how he came out to his friends, on the homestuck album 10 commercial thing its mentioned how the strider boys are in trouble again and not just because kissing boys is illegal
the whole conversation between dave and john and karkat about compulsory heterosexuality and toxic masculinity. about how he had this insecure idea of what it meant to be a man and that being gay was a big joke and he made it into a joke to hide his own feelings about it. (plus Dave’s not so subtle jealously about the fact that Karkat may still have feelings for John)
before the retcon timeline we KNOW they became best friends. they refer to each other as such. the reason it took so long for them to be friends was because of theri mutual pining for Terezi.
post retcon, they no longer have to worry about fighting over her since Terezi has John’s advice from herself not to date anyone. She doesn’t need them. and they become friends much quicker. and their relationship grows naturally.
during Vriskagram we get to see glimpses of their friendship. a friendship which includes holding hands, smiling, cuddling, being happy. Something that is RARE for the two of them. Something we’ve never seen them do with ANYONE else??
Vriska and Terezi’s conversation about Dave and Karkat’s relationship and how Vriska thought they were adorable.
Roxy’s lightening round and Dave’s reluctance to talk about being in love or kissing anyone. If it wasn’t a THING, why would he be so embaressed? Why wouldn’t he jsut say ‘there’s no one’ or make something up?
And finally, Davepetasprite’s two parts. Nepeta who had a HUGE crush on Karkat. They say how they actually aren’t conflicted about their feelings for him as they thought they would be. That their romantic feelings still feel right. So, Dave liked Karkat too.
we never got the true IN CANON confirmation. But, tbh MANY ships never officially got that. But, homestuck has hardly EVER done anything like that. And in comparison to lots of other ships, they have TONS of confirmation.
The point being that despite having TONS of evidence and confirmation, people still continue to deny it. Whereas if their relationship was m/f no one would argue. I’m sure people would continue to ship whomever, that’s fine. But, this isn’t just some fans who want so DESPERATELY to believe it. It is canon.
People can ship whatever. No one can stop you, really. I’m not telling you not to. But, stop acting like they were JUST friends, like their relationship never was a thing.
They are good for each other. They can see past each other’s facades. They have similar humor and talk a lot. They call each other on bullshit and defend each other from those who take it too far. They both have had such a rough life and need someone who understands that kind of isolation and pain. They see the TRUTH in each other and help build each other up. Karkat is calmer, more level headed, happier. Dave is less prone to playing serious stuff off as jokes, he’s not as worried about living up to an impossible standard, he’s happier.