From what I understand, there was no scam accusation against the casinos but they are operating illegally in their country. By illegal it means they are operating without the necessary licenses and probably no documentation and no revenue to the government. The celebrities were arrested because their activities look like supporting that illegality, something the government see as unpatriotic and misleading to the general public. It's also important to note that as the casinos are operating illegally, it will be very difficult for the government to protect their citizens from losing money to them and in the case of the casino operators running away, there will be no way of getting them because they were not documented.
They are not registered and have no license to operate. And it means no protection to its consumers or customers that have been gambling with an illegal casino.
That's what the government is all about, they want to get these illegal casinos registered for them to be taxable. While these casinos don't want to cooperate with them.
They just get an endorser to promote them even if they're illegal because they can just run away from the government. While their celebrity endorser is the one to face all of the lawsuits or any punishment that the government will have to put against them.