I ansered that question initially, by stating that I respected the individual not the position.
In industry (my industry) you have a quite regimented system, if I called a supervisor an idiot that could be classed as insubordination and act of gross misconduct which could lead to dismissal.
If a supervisor called me an idiot then I can complain, and that's pretty much that, some supervisors you can frank with others you can't because they think they're better than you.
I agree about good manners, but, that only discerns if someone has class, it doesn't define their class as posed in the question.
For instance Hitler was a gentleman, as was Pol Pot (he was very amiable apparently), whereas Churchill and L.B.J were quite rude at times.