I have no idea why Davekat became so disliked. When I reread Homestuck late last year, I was pretty much stunned by how immediate the chemistry between them is. Even the limited hostility between them in Act 5 Act 2 feels pretty gay, in retrospect. I feel like maybe some people dislike it because they were (perhaps understandably) invested in the knights ending up with Terezi or Jade or John. But idk. First crushes and relationships don't always work out. Sometimes it's the person you didn't expect, right?