It seems they don't play about this in some countries and I think that's how it should be. But if the gambling company is legit and doesn't scam people then there's absolutely nothing wrong with taking endorsement deals from gambling companies. In my country celebrities help to advertise scam casinos and this is actually the main problem and it's what must be corrected but no one cares to call them out
Illegal casinos are also likely to scam.
And that's a good concern for the government to call out celebrities that are tied with the endorsement for illegal casinos.
If they can't register yet can avail a service from a celebrity, there is a lot of things that are telling in that point. They don't want to be registered so the government is free to chase them while these unregistered casinos endorsed by them can also do whatever they want with their customer's deposits.