What is this 'sentist' and 'humanicentric' thing you speak of? Was he fired by his cat?
He was being very biased against the company he used to work for.
isn't this normal? as long as he's not posing a threat to anyone, just let him be. if you are telling him that he's a bit unreasonable, he might think that you are antagonizing him. if he's an emotional and hard headed guy, there's no reasoning with him. i've dealt with A LOT of people like this before.