why is google banning people for no reason?

Ya google won't ban anything without reason and they won't give any specific explanation too. because it could be automatic response. And it would increase their cost of operation to explain every ban. millions and millions website are signing up for adsense and I believe the banning rate could be high. because it is our mentality to just do anything we want and if someone found out we do bad thing they have to explain to us. but guess what? they didn't know who are they dealing with.