"have multiple accounts and selling accounts is prohibited in the Forum".
It's not possible to prohibit it in reality. That was made clear why it's not banned-
Q: I saw a guy selling Bitcointalk accounts. Why is that allowed?
A: Since we can't effectively prevent these sales (proxies, TOR, sales on other forums), we don't because otherwise we would be giving the users a false sense of security.
Having multiple accounts have no problem as long as they are known, but if they are unknown, theymos will not know if they are using TOR. So, it's not easy to prevent.