If you play a PvP game and/or go into a PvP zone, expect PvP. If you keep getting beat by someone who is playing by the rules, then get better. If there's still no way for you to beat them, then it's on the game developers to balance the game. It's that simple.
I suppose you are of the opinion that screwing over other people IRL also is all right, as long as it's legal? I mean, if it wasn't meant to be done, then it would be illegal, right?
But it wasn't PvP. The professor took advantage of the invincible NPCs at the ends of the area to kill the other players.
If he had simply been a bully, picking on weaker players, the situation would have been different. The professor was exploiting a loophole in the structure of the game provoke a reaction from other players.
He broke a social contract, not a game play mechanic.
It's like fat people walking down the middle of a narrow hallway; there is not explicit rule that prohibits that. But they are still breaking implicit rules which pisses people off.
PS: People don’t clearly separate games from real life. If you follow to closely to an avatar in an MMO for to low it will also bug people.
The means by which Myers was winning did nothing to establish himself as a skilled player. People were not using his strategy precisely because it required no skill. Myers was not using the area as intended but rather abusing a loophole (that was later closed by the game admins).