So admins here just are ok with it because that is the easier way.
Easier for who? I've been banned and had my posts removed for extremely trivial things compared to impersonating another user, so, I don't buy that they don't have enough time to monitor the situation.
All account trading should be banned. They should at least attempt to make it more difficult.
How long were you banned for? Was there an expiration on the ban or did it just say you were banned?