It is worth considering that fraudulent projects stamp their casinos for the sake of a deposit, and the administration of bitcointalk would be better off taking a security deposit to protect such cases. I think a serious casino would not refuse to pay the administration of bitcointalk a security deposit for publication on the site
The administration of Bitcointalk does not moderate scam and so, I don't think they would want to be involved acting as escrow providers for Casinos. The admin can barely make any new feature developments for the forum. It seems he's a very busy man, what makes you think he will have time to take and demand for security deposits of hundreds of casinos listed here.