Doc Scratch is an exercise in trust between reader and author. when he takes over Homestuck’s narrative it’s natural for us to distrust him on instinct: we were used to the other guy telling the story, who’s this new guy and what are his credentials?
but by that point we already know that “the other guy” was just a fallible human; one locked in an attic by bullies and tormented by stuffed wolf heads, no less. the only reason we have to “trust” the first guy is because he’s the devil we know. when Hussie calls Scratch’s version of events “troll fanfiction” there’s no real reason to believe that Hussie is “right” and Scratch is “wrong”; whether we choose to believe one author over the other is ultimately arbitrary. indeed, out of the two, Scratch is the only one with any real claim to “omniscience”, even if it is partially compromised omniscience; so in all possibility we should believe him over the human one, right?
probably Scratch’s main qualification for reliable author is that he does not lie. but if you already distrust this guy, what reason is there to necessary believe him when he says this, right? he could be lying about lying. so in truth whether we believe what Scratch says or not is, once again, totally arbitrary. like Rose’s inquiries as to whether the Horrorterrors are evil or not, this is a fruitless line of questioning that ultimately achieves nothing. more important questions present themselves; why might Scratch be lying or telling the truth? what reason do we have to believe - or disbelieve - the things he says?
I’ve pointed out before that Scratch’s policy of honesty reflects less on himself and more on Homestuck’s narrative as a whole. Hussie’s own commentary makes the exact same point: “…this is where some of his views as a nefarious alt-author figure start leaking out. If you imagine that his spiel here is being applied to a philosophy on storytelling, it tracks pretty well. […] He isn’t even that much worse than me in terms of things like authorial sadism, jerking the reader around in certain ways, self-indulgence.” (Homestuck: Book 6, p. 388) So in deciding whether or not you “trust” Scratch, what you are really being asked to do is decide whether or not you trust Homestuck itself; you’re being forced to either engage with Homestuck on its own terms, on the merits of its own themes - or to disregard the text entirely!