There's a running trend with the anti-rwby sphere that they not only hate the show, but absolutely despise all the people involved, right up to an d including the fucking VAs who are only involved insofar as they read bad dialogue off of a piece of paper. Floof artist is another one, the guy got clowned on by Barbara once at a con and has made it his personal mission to be a snide prick to her at every available opportunity since. There's a definite level of jealousy that seems to seep into all these people, they aren't very talented and they project their insecurities onto the cast and crew because RWBY is terrible but managed to be successful anyway. It's like kryptonite to self-obsessed weirdos who feel entitled to the success of their creative endeavors.
It really is a near jihad-level fanatacism, and you're probably right that it's rooted in a lot of jealousy. Every dedicated RWBY critic I know of is some sort of failed artist, the type who believes success should just come to them because they say so, regardless of skill, effort, or willingness to learn. Celtic, CJ, and Media are all over 26, all wishing to be professional writers, but have yet to make any sort of real impact in their lives, or even
want to leave their parents' homes. They all have their RWBY rewrites where they get to lord over the one thing bad enough for them to have some kind of power over, whether that's true or not. It's like an autistic kid bullying a more autistic kid then getting furious when his victim remains happy and successful, furious to the point where he hates all his victim's associates, too, even down to the teachers who like him.
But when those "aspiring writers" are faced with the actual challenges involved with honing an artistic craft, they fold. They don't read more than manga and fanfiction, so they don't even have a basis to aspire to. They think they can just
know, because they're special and uneducated like Monty was, so they can be just like him. They claim to want critique, but can't comprehend why anything they did could be fundamentally bad. So they hide behind the usual excuses when asked where their writing is: it's such a long series, there's so much lore, I'm still outlining, etc etc. Even non-writer Floof has a similar issue. Though he goes to school for animation, the homework projects he's uploaded are lackluster, and the advice he gives is uneducated. The arrogant simply can't be forced to learn.
Side note: Holy shit, I did not realize CJ accused Arryn of lying about
her own abuse when there's "no evidence," as though abuse can always be empirically proven. Big talk from a man who broke up with his girlfriend because he couldn't help but m'lady cosplayers.