I think you are right that we do not read all the rules and if we read also we do not remember unless we have a bad experience like infraction. may be this is normal human tendency.
I also think that it is because of the carelessness of the members. In every organizations there are sets of rules which every member should follow, otherwise there will be chaos and there will be no order.
People don't read them, also though I think it is the lack of respect for others that may cause people to be banned.
Yeah I guess when you join a forum as large as this one its hard to know all the rules, but the main 3 only should be clear on sign up in bold.. the rest well you should get infractions along with temp bans with clear rules saying what for..
You may be right, for some people it is fun to break rules. Otherwise if all the wrong doings are due to a mistake there wont be so many problems in the world. And also some people are just careless.
The best answer is their is no rules behind money. The majors way the get banned to spam and get visitors(money) or scam others..
After studying response from all you guys i came the following conclusion: It can be any reason like, people are dumb, they dont care, they dont know, they dont read rules, total ignorance or any think we can think of.