I know mods talked about the reason for the ban but perhaps one of the reasons was selling verified accounts.
If you did anything illegal in order to obtain an item, then you can't trade it on bitcointalk.org. Anyone found breaking this rule will be banned.
[WTS] Verified Bittrex, Cryptopia, Cex.io, NovaexchangeNo... I sold few of my own accounts, which i have made personally. Afaik there is no rules against that, also selling verified cryptoexchange accounts does not include trust whatsoever.