It is not illegal to buy or sell accounts but it does not matter, the point is that he was scamming on his alt account and now he is complaining that he got negative trust on this other account which now makes no sense.
isn't it always against rules to buy/sell/trade forum accounts?
It isn't on this forum, though I find it extremely sketchy.
It's quite a big market actually, most of the action takes place via Private Messaging. If you get negative reputation/banned, it's not meant for just the account, it's meant for all your accounts.