No, this form just has rules. If you take the time to read the rules, and then follow them, you will not get banned. Thats how things work sometimes in life. You go places and they have rules they expect you to follow for the privelage of their use. You don't follow those rules, you're warned. You continue to ignore them, you're no longer welcome.
I don't know why you got banned, as I am not a mentor or moderator. But ask youself, did you break any rules? Remember, this is NOT a completely open public forum.
As for the dictatorship bit, yes it is, a bit. But that's how all private societies/clubs/companies/etc work. The people who own and operate set the rules; it is their right to do so. Is that a little like a dictatorship? Well yes, but unless you're a shareholder of a public organization you don't have a right to vote.
(not trying to be a jerk, really, but just trying to be clear in a "thats how it is, get used to it" sort of way. Seems like all forums are getting stricter to keep the crazies out.)