Provably fair is literally "provably" fair. It is not "that is what we assume it is", it is literally "you can check it whenever you want and see that you are not getting scammed". People who still think that a casino is scamming them in this day and age when we have literal provable data that shows that casinos can't scam you, sounds really like a person who has no idea what is going on.
No the casino didn't scam you, you just hit an unlucky streak and lost your money, it happens, it happened to all of us, you will get used to. Instead of accepting the reality of the situation, trying to create an imaginary situation where you get scammed otherwise you would never lose that much, will only hurt you longer, doesn't really impact the casino or other gamblers.
Provable fairness means you should be able to mathematically prove the result of a bet. It does not mean you cannot get scammed. Provably fair is not infallible because
it can be exploited or as was the case with Coinpot's multiplier game they can just make up any result they want and hope people aren't bothering to verify each roll.