It's allowed because they can do whatever they want. It's their table and their cards. As long as they don't welch on payouts that you've already earned, they can kick you out for any reason (except belonging to a protected class), or for no reason.
On this note, don't gamble in casinos on reservations. They are not subject to federal regulations, and they absolutely do kick you out without paying if you win big enough.
Only in casinos, though. It'll be the new wild west - a gambler's marketplace of ideas, where only those lucky enough to win big can spread their ideologies.
demonstrably rigged game fueled by ignorant rubes who all think that they're the only person there who isn't and where the only way to consistently win is to already be a winner
I think you two are talking past each other. "People wearing swastikas" is not a class of people because nazism isn't a religion. They are just people making a choice to wear a shitty and offensive armband. Classes are about things people either couldn't possibly help; such as nationality, race, sex, disability, color...or things so closely tied to their identity that they should never be expected to change; such as gender, sexuality, and religion.
Then there are some outside of the standard discourse as well, like prisoners are a protected class when it comes to psychological research.
"Prisoners are one of the federally-protected populations of research participants. This status, accompanied by additional regulatory requirements and ethical considerations, is designed to reduce specific risks that may be experienced by this vulnerable population. This includes confidentiality risks as well as vulnerability to undue influence on the decision about whether to participate in the research."
Politics are an interesting issue, although not a class. California, for instance, prohibits employment discrimination based on engaging in certain protected political activities. So if you attended a Nazi rally, you might be legally protected in California from having your employment terminated.
I don't want anyone to have the power to kick out people from public places for arbitrary reasons. Defending against Nazi's isn't an arbitrary reason though.
Casino's like Capitalism, shouldn't exist. That isn't to say you can't have fun playing poker etc, just that the Casino's as they exist in our current hell world, only exist because they pray upon the downtroden. That they exist at all is a symptom of a sick society.