Casino just unaccepted for their lose, they want an identities (who have enough money) as cashback.

They possible to selling your data at darkweb(Your data could being used as terrorist , loan crime and etc).

If you baby fish, they wont ask that. Strange T&C/ToS.

They should asking all user ID before let deposit. Poor Casino.

BET ME!, Once you have big withdraw. They will be asking for KYC. Then you will trade your ID with your winning. You are lose not winning.
BEWARE.