I'd say he's more bitter than crazy
but being bitter doesn't make him sane
even if he has a legit reason to be bitter
he's bitter over situations where he felt he was fucked over
but if we agree with Alan Moore that Alan Moore was fucked over, than it really just makes him look even more crazy
his bitterness could have been used to do productive things
like Image comics being created when Todd McFarlane felt that Marvel and DC were fucking over the creators of individual comic characters
and instead of bitching about the industry as a whole (the industry which gave him all his money and the fame to have people hear him bitch)
he could just be bitter an bitch about the specific people that fucked him over like when a writer/artist gets pissed off at one comic company and starts doing the exact same job working for another, or how Nicolas Cage ended up playing Marvel Comics character Ghost Rider only After the whole thing where Nick Cage almost played DC character Superman
Jack Kirby died broke
Jack's wife kids and grandkids blamed Stan Lee and eventually became super rich by winning a lawsuit where a judge basically agreed with them that Jack had gotten fucked over and should have had a fortune in his bank account when he died
Alan Moore getting fucked over isn't resulting in Alan Moore making more money or any kind of improvement of the industry he's complaining about
it's just resulting in Alan Moore making the crazy rants about how superhero culture somehow affecting political elections and causing Brexit