The race fanwank is coming up again on Homestuck Twitter and I thought this might be a safer place to discuss it.
To begin: Andrew Hussie is a white man with a white perspective. I am white too.
Andrew Hussie created a handful of interrelated humans to survive a global apocalypse.
In his now-deleted formspring, fans asked what race these characters are. He said they were aracial. These highly-stylized characters were whatever the reader imagined them to be. Wonderful idea.
However, the Text of Homestuck before
and after this declaration undermines this. John calls Dave's Bro white. The trolls refer to the humans having pale skin. Vriska notes that John is hugging a "brown human" (Crosbytop) which suggests John isn't brown. (I actually think though that Trickster Jane being Caucasian would mean Jane isn't normally Caucasian). There's a lot of little things and big things.
Hell, Hussie's Word of God undermines his Word of God. In that same formspring answer he says the humans aren't black. He lampshades that as racist but doesn't explain why they can't be black.
I think that fans should ignore both the Text and Word of God. Homestuck is a very
very imperfect work and if fans can improve it they should. But if in the end the fans imagine the humans as white that's Hussie's fault, not theirs. Just as long as they aren't assholes about POC headcanons.