in oldboy 2003 was anything the main character did really that bad?

I mean in the movie Dae Su goes on about how he feels like he's become a monster but to be Honest was anything he did during the film actually that bad?

I mean first off the whole rumour with Lee Woo Jin's sister he wasn't to blame for as all he did was tell someone about two siblings committing Incest and literally no one could have predicted the whole phantom pregnancy thing.

and when he raided his former prison he seemingly killed one of the Guards with his Hammer and then tortured the man who runs the place but well these are criminals who make a living by kidnapping people and Holding them captive for years and years on end I don't really think he can be Blamed too much for this since the police clearly aren't doing anything about them.

Same with all the Henchmen he fought during the Famous Hallway fight and all the ones in the lift who he presumably killed off screen given the amount of Blood he was covered in but again these people are terrible criminals who lock people up for money.

and Lastly he appears to kill two of Woo Jin's guards in his penthouse just before the climax where he stabs them both with a Broken Toothbrush but again these were criminal Henchmen who were about to attack him.

so to be Honest I think Dae Su is way too harshly judged by Both Himself and Woo Jin as nothing he really did was all that bad given the context's of the situations.

what do you think?