Don't worry, I think the silent majority is on your side.
If someone is defending "customer is always right", then they've probably never had a client from hell.
Which is why you need to cultivate a zen-like calm when dealing with them, otherwise they will hurt you
I agree with your position.
People have become so entitled in all aspects of life, that they forget that there are people on the other end of their abuse.
The capitalist motto that "the customer is always right" has created the most entitled generation of rude and abusive customers.
People condemn individuals who are rude to their servers, but it seems to me, from the reactions in this thread, that they would just as easily condemn servers for pointing out the rudeness.