Sure, I am against mob justice. Though, yeah, if as reported this has been behaviour he's been known for, then yes, there should be consequences. Not as punishment, but for the good of other employees. Making a public post is not a way those kind of complaints should be reported. However, again and again, those seem to be the only ways of getting things done.
It's not up to me to discern if it really happened or not. But if that behaviour was his norm, I do think companies should do a research before putting him in a position of influence.