Even if he does, it in no way whatsoever excuses his awful behaviour, abuse and harassment. And it is cowardly and incredibly insulting to those who do suffer from it to claim it is.
It's not a carte blanche, but acting socially inappropriately is a hallmark of Autism-Spectrum disorders. I do believe that does excuse or at least re-frame certain behaviors that might be otherwise construed as "awful" or "abusive". Intent matters.
It really, really does not. I think you should try to first go find out what the behaviours actually are. It's not just having awkward opinions or butting into conversations.
He also ate ”something” from his own foot, in public. I’m not saying his behavior is not highly inappropriate for an adult man. I simply refuse to attribute malice. He probably thought it was hilarious to lick the arm of someone he just met.
It depends. I haven't heard of him licking anyone's arm again. He does change his mind if you can convince him. Otherwise, he is just going to be inappropriate in novel ways, because he can't tell what inappropriate is. Also, if he disagrees that something is inappropriate and you fail to make a convincing argument as to why it is, he will not change that behavior.
Short of calling it a diagnosis, those are all hallmarks of ASD, which you should recognize if you have ever dealt with such people in depth. If you haven't, consider moderating your judgement.
Look. Pretty much everyone who has interacted with him keeps saying, over and over, that he is an absolutely awful person, that he is abusive, and that people keep telling him this and he keeps not doing anything whatsoever to change.
I am going to choose to believe all of those people, and I am going to choose not to insult everyone suffering from ASD by claiming that that is how a person with ASD acts.