If a casino does this, I think they hope that someone will make a deposit and lose money in the meantime. If you don't allow a player to withdraw without kyc - you shouldn't allow him to deposit either. Such practices prove that the website only cares about profits and does not care about the user.
As much as I agree with you, I also will not blame casinos entirely for this type of move, reasons being that, most casinos gamblers hate kyc, and as soon as they sign up on a casino, and the casino ask them to pass kyc verification before they can be able to deposit and play on the platform, that gambler will immediately abandon that casino and go for another one where they can deposit, play without having to go through/pass kyc verification.
This is majorly why a greater number of casinos this day would allow a gambler register, deposit and play without kyc, but the moment that such a player wins and requests a withdrawal, such user will be asked to pass kyc verification, and they do this at time of withdrawal because the gambler have no other choice or option this moment, other than to submit the requested documents for the verification, doing otherwise, the gambler may never be able to access his or her money, lol 😂.