These types of deposit agreements are necessary for Casinos to not be taken advantage of by free rolling users. When you make a deposit with a bonus you agree that you NEED to play a certain amount of money or spins, or whatever the agreement is, before you can withdraw the money. It's industry standard and you being mad at what you agreed to is pretty ridiculous. Good luck on your future gambling!
The "industry standard" is actually more like 35X the deposited amount being rolled over on real money casino sites.
2X roll over is quite low. The only other "solution" a bitcoin casino
could do is to remove the bonus amount added on your balance and give the portion of your deposited amount leftover. That's not "easy math" though, so the agreement has the 2X requirement.