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.
That's totally fine. As much as I love the show, I appreciate it's not for everyone. It relies on a lot of pop culture knowledge and awareness of tropes and memes. It's perfectly reasonable that he doesn't get it. I wouldn't be surprised if Jonathan Banks didn't get some of the jokes either.
This explains why I didn't get it. I thought Community was ok but never understood why it was so popular. To be honest, I didn't think it was funny. Guess I just don't get pop culture references. ¯\_(ツ)_/¯
True, but it's still a dick move to say it. And a narcissist move not to comprehend that his frame of reference, and his sense of humor, is not the only one that matters. Of course, maybe we can forgive him for saying it, since he's probably just mad about being fired from the show for saying slurs to the cast.