The 30x or 50x requirement is probably for the bonuses whichever casino has that requirement, it can't be for a normal deposit because even 3 to 5x is a lot when it comes to withdrawing the money you've deposited.
X30-X50 is actually standard wagering requirement for deposit bonus, but if you look at the other thread created by OP, you will find a casino that ask you to wager x10-x30 for deposit without bonuses. I havent checked myself, but it proves that high wagering for normal deposit does exist in the gambling industry and I believe players will not stay long in casino with high wagering requirement for deposit without bonus.