And Jinwoo is no longer human
Says an elf who glitches out.

The elf came to that conclusion because the system didn't tell him to kill MC with their blanket rule, thus assuming he's not human - according to the system. That doesn't mean the MC ain't human in the conventional sense. It just means he has a special category or status with respect to the system.

Go ahead and kill that lower rank guy, but then rot in jail, you asshole.
He'll become a fujitive, though you can kill in dungeons because no one is able to report it, and it probably doesn't fall within anyone's jurisdictions, but also - how are you going to keep them in jail? Enforcement will be an issue even if they tried.

Okay. Then the anime producers probably shouldn't design her as the ultimate fap material with perfect face, boobs, thighs, ass, etc..
Nah. Underaged girls are allowed to be sexy. This is like "if I'm not allowed to have sex with you, please put this burka over yourself so I'm not tempted" thought.