In casino movies, casinos often kill people who win or beat them up severely. Is this allowed in real life? Why does it happen in the movies?

ATM: I'm watching this movie called "The Cooler", got to the scene where a couple (man and woman) gets kidnapped and taken to a basement presumably to be murdered, because they won money in a gambling game.

I just think this scene is exceptionally ridiculous. Surely casinos IRL aren't allowed to just murder people because they won, right? Why did the director make this scene? What is the point? It sucked my immersion right out, it seems so stupid. Wouldn't this get the team arrested, and sent to the electric chair? I mean there's tens of thousands of visitors every day, so that means the casino regularly kills dozens of winners every day??? What an asinine plot.

It's not realistic, or is it?