I wonder if the guy can be reported for Inappropriate behaviour, as the description for it is as follows:

"Inappropriate Behavior
Behavior intended to prevent or hinder other players from fully enjoying the game is prohibited. While SQUARE ENIX encourages unique play styles, SQUARE ENIX may penalize players who hinder or diminish the quality of game play for others through inappropriate behavior"

It's safe to say, this guy is hindering the enjoyment of the game.