this.
while I haven't card counted at blackjack since covid- the amount of bullshit casinos have pulled with APs is disgusting. Granted it's not the 1970s anymore but they're still shady. While MOST backoffs in bj are perfectly professional some are not. I haven't experienced anything nearly as bad as you, but to be fair I've also never been part of a team. Casinos tend to go even further against teams than they do individual players.

As for why i frequent casinos- primarily bc that's where poker rooms are.
Additionally to card count in blackjack and take advantage of various promotions.

I've also had to get the gaming commission involved on several promotions in legal regulated online sportsbooks/casinos to get them paid. And a lot of these sites are owned by the same people who own brick and motor casinos.Fortuantely this site are still run by complete idiots who don't understand 8th grade math. The funniest incident was having an offer which gave me a ton of free bets for the sportsbook if i bet x dollars. Once i got the free bets the site cut my limits to dirt rendering the free bets basically useless. Since they wouldn't raise my limits to use the free bets they ended up giving me cash for the same amount as the free bets once gaming got involved which was even better than just letting me use the free bets.

To be clear I can understand a site/casino refusing someones business (although it is funny when their slogan is "Philly loves a winner.) But they should still honor any promotions you're owed. They should cash your chips in immediately not refuse, call the cops, intimiadate you into giving them your id, lie about the law in an effort to get your id out of you, shuffle up early in blackjack in good counts which is flat out cheating everyone at the table etc. And obviously stuff like back rooming is taking it to another level.