When you deposit coin into a casino using bitcoin, the coin you receive from a withdrawal will not necessarily be spend-linked to the deposit transaction. So if you have stolen coin, you could deposit it into a casino, and the withdrawal you receive would not be associated with that stolen coin.
Obviously, law enforcement could simply ask the casino what happened to the deposit, and could then continue to track the history of the coin you received.
Oh, OK.
Since I play poker on fiat sites, I wasn't thinking about that.
Of course, I realized that a long time ago. When you deposit, at least in the crypto casinos I have deposited in, you deposit in one address and when you withdraw, you get the money from another address which is the one they use to consolidate inputs. Normally if you deposit today and withdraw tomorrow, probably the money in the address you deposited will still be there, without consolidating.
Anyway, I think this excuse is bulshit, and even more if we talk about 300% of wagering requirements, so the probability of losing your deposit will be close to 100%, because we can say that some people use casinos to launder money in the same way that we can say that some people use mixers to launder money, and in case we want to investigate, we could follow the trail with the collaboration of the casino.