You are factually correct and sum it up perfectly when you mention "rich man's justice" but you know as well as I do that realistically no one sues for libel apart from famous people and multi nationals. It just isn't a viable option financially: even finding a lawyer who will entertain looking at a libel case is hard work.
People don't realise it isn't a case of proving someone said something defamatory, it is proving it did indeed have a detrimental effect on your life or business as in it was seen by your contemporaries/colleagues.
I would suggest posting something on FB is pretty much guaranteed to be seen by contemporaries and colleagues!
However - my own personal opinion is if you say X casino is rubbish or badly managed etc it shouldn't be a banning offence. There is the angle though that if you think it's so bad why do you want to go there anyway, so a ban shouldn't be a problem. Obviously if you say people are cheating and the casino knows this you are walking straight into the line of fire.