@meangreen
That's like saying violently and maliciously torturing terrorists is "justice", when in reality all you're doing is to satisfy yourself.
Actual "justice" is to either rehabilitate "evil", people who skew off basic human morals, or simply banish / kill them off swiftly. Anything else is self-satisfaction and clearly shows your own character.
So, yes. The MC is a bad guy. But he can be sympathized with, since he fucks with greater or equal evils.
@AyyGiraffe
How's he as bad as the rest of them?
Well, here's a clue...
He's clearly replicating the same level of sadistic evils that were inflicted upon him...He clearly *enjoys* being this horrible as everyone else.
So, yeah. The entire point of the story is that he tries to reflect the same amounts of evil towards the people who acted atrociously towards him.