You write "That’s the point".
But you asked a much broader question.
I gave two examples, one real ("Jimmy the Greek"), and one hypothetical ("pinko Commie"). Do you really want to get into a discussion of how it was not "right and just" to fire Jimmy the Greek for his racist comments?
That’s the point. If it were harassment, false accusation of a colleague, etc, it would not be merely expressing a bad opinion. But as you say, none of those apply.
And I think it’s clear I was not raising an issue of what is legal, but of what is right and just, and desirable for a university, for a workplace, for a society.