The writers of Community had a fun little game. Someone puts forward a racist or otherwise offensive statement. The rest guess if this was something Pierce Hawthorn said (Chevy's racist character on Community) or something Chevy said himself on set.
My recollection from interviews is that Dan Harmon and the cast found Chevy just didn't get the show at all when they were making it. A huge amount of Community's humour is a mix of meta humour and pop culture references. In the same way that Pierce claimed to never understand what Abed was talking about, Chevy didn't understand most of what Community was on about - his frame of reference for what is funny hadn't moved on in decades.
Even though he's famously a dick, when he says he didn't think Community was funny, he might actually be telling the truth - not just being petty.
Sorry to link to reddit, but the hobby drama about this man is wild. I'd call him a bitter old man if he wasn't already this much of an asshole in the 70s.
Its not really what he was saying, but he could have had a point. The shows writers really did kind of have it out for him (with good reason as stated everywhere else), and as a result they didn't give him very much to work with. Even his use of the N word was directed at the writers, saying something like "pretty soon they'll just have me call Donald N----r". Its really a vicious cycle, because it's hard to write good jokes for a person you dislike as much as the writers did chevy. And then Chevy gets even shittier to you because you constantly give him the worst lines.
I've seen quotes from damn near everyone else on Community that has said Chevy is a bastard to work with. If this is his attitude about the show, I can see why they would say that.
Chevy not being in the movie is a damn shame. I always envisioned the story being Troy sailing to find hidden treasure but it turning out to be Pierce after having faked his death.