there is nothing wrong with anything related to marketing tricks as long as you are forced to try it then it is legal,, if you are lucky then you can make a withdrawal with the registration bonus that you get, of course, with the conditions that you must follow. don't stop trying, who knows you will be the next lucky one.
I agree with you but users must understand that differen bonuses is just a marketing campagn and advertisement but not a gift or present.
Most casino bonuses are subject to some wagering condition, if a player does not meet the amount of wagering requirement to allow withdrawal then their will be denied their withdrawal, and if you pay close attention to the casino withdrawal terms and conditions you will see where all the conditions are mentioned there.
Most time, some players accuse the casino of holding their withdrawal or denying them due to not meeting up with those conditions and outline in the terms of service of the casino.
Players should know this and try to meet all requirements before placing a withdrawal request.