That is always what the player says do not violate and so on, when a casino blocks your account could be they find something suspicious from your activities, they run a signature campaign with a budget why harm the reputation
That's normal, the unfair thing here is that the casino didn't tell what are the specific reason why the account was banned, it was not clear on the message OP is received. They just tell suspended user their generic reasons of suspended account from their terms.
Also, having a signature campaign doesn't mean that the service is legit/reputed and won't do any unfair thing to its users. There are already lots of them, from reputed to negative reviewed site/casino.