Criminals may well launder money through casinos. To do this, they need to negotiate with the management of the gambling platform. It is risky, but money laundering through online casinos is a common way for those who are engaged in illegal activities. The management of gambling platforms receives a good income from such shady activities.
Lol, can you name with casino has done that in this forum? it's hilarious how you can have thought like that.
The reason why centralized casinos has a money laundering rules is to avoid future problem, blockchain analysis can track where the transaction goes on since public blockchain can be visible to everyone. Also the other reason why the casino ask KYC is to make them know who's control the account and if the money is used for laundering, it can help the police to catch the criminals.
Build a casino is already profitable if you have decent gamblers, they don't need to help criminals to laundering dirty coins.