It’s funny how people are always the hero in their own story. I am not sure what your management was supposed to do with a bunch of hearsay from another company. Allowing a previous company to blackball an employee sounds like a good way to get sued if you
ask me.
By “attacked” I’d have to assume you mean a verbal altercation between employees otherwise, I’m not sure why the authorities were not contacted. It sounds like there were probably issues with this guy, but what can be proven and what your opinion of a given situation is are often not the same.
I am not sure how one “Captain Angry” makes an entire organization not supportive of their employees. But hey, you didn’t get what you wanted so it has to be someone else’s fault.