Try holding more Aggro next time.
On a more serious matter, Rule 10. Resetting a boss to full health to gain control of the loot is forbidden. This will result in a ban.
I don't believe he was resetting the boss to gain loot control over it. Instead it appears as if he accidently aggro'd the boss, then ran to avoid death.
P.S: Just because he says he doesn't like someone, doesn't mean we're going to weigh his ban ( I won't anyways, others might) Everyone has their own opinion.