Actually, there is no written wagering requirements on the ToS which only mean that they doesn't have any wagering requirements to withdraw. But ofc you will be suspected mixing if you withdraw immediately right after you deposit. Their x5 wagering requirements for suspected violating their AML policy through mixing is fair punishment and safety protocol to avoid crime under their nose.
The list should be plain standard wagering requirements and not including the special case if you want to make it a valid list for high wagering requirements.
I agree with you, a fixed wagering requirement in case of suspected misconduct is far safer for users than a scammy endless KYC that no one is able to pass. Unfortunately many unprofessional crypto casinos, including the biggest ones, don't hesitate to scam unwary customers by using the AML excuse. So this kind of rules is actually a good point for a casino IMO.