I can understand when the Chinese government prohibits gambling sites because many players from China lose everything they can and their families suffer ...
But why countries like the USA, France and Germany do this, there is only one option - the authorities of these countries do not think about people, but about the fact that it is difficult to keep track of casino taxation, and the income of the owners. So they make primitive prohibitions at the level of laws. Especially the USA, in Las Vegas you play as much as you want and lose, but the site is prohibited ...
I can't speak on behalf of this specific website or any other, but I remember the pokerstar thing back in the day, it got raided by FBI so it wasn't like a small thing neither. Usually the law prohibits people from starting a casino wherever they want, so there are limited places that they can do it, however withdrawing is not limited, which means that you can deposit money to your pokerstars account from some Bahamas bank and then withdraw it to your bank of America account.
This created a bit of a loophole, which allowed people to move money from abroad to USA, which normally would be a good news right? Every nation would want money to go into their nation non-stop all the time. However it was always obvious that this would be abused by drug lords and money laundering, so that ended up being a problem for pokerstars as well. That was one website though, I can't speak on behalf of the whole law.