There is a provision in the rules for accounts to be transferred, but not sold. I find it odd that you would believe the claims of random players and then assume, based on their specious claims, that Inno is not fairly applying game rules. Especially when you have no way of knowing either the truth of whether the account was actually sold or whether Inno actually did or did not take any action.
There was a very popular game that required you to Quest Ever-ly which had a similar prohibition against selling accounts.
At first, they seemed not to be aware of it, even though eBay had hundreds of listings of accounts for same, some costing several thousand dollars. There were even several websites dedicated to either selling outright or auctioning player accounts. Once they were made aware of this, they made that players were aware of this TOS violation- at which point players claimed that they were not selling the accounts themselves but rather were being compensated for the time they'd spent to get their characters to the levels they were.
It took a lawsuit to establish that, too, was a violation of their TOS.