Do you not hear what he just said? He asked you for practice saying he's not tournament ready, yet when he lost miserably he flipped out and said remove him from the tournament. A reaction like that means he had some expectantcy to do well or even win, and if he's going to flip out over a loss is he really worth keeping. If he asked for practice and lost, reguardless of how bad, he should've continued to practice, ask for pointers (which you so generously gave) and work toward bettering himself.
However, despite all of that, I would not remove him from the tournament even though he asked. When people talk out of anger the usually regret what they say (even if it is the truth at the time).
My comment to Steal would be that Brawl is experienced based. The people (except for a few) who are really good have played Melee and migrated to Brawl.