to be evil? or at least fucked up in the head?

I've heard he tried to actually kill a guy by throwing him off a scaffold, onto the turnbuckle, the way Owen died. Sounds like a massive cunt.

^not only that.
He almost murdered a nearly 60 year old Indy wrestler in a small venue; he nearly killed a 16 year old kid that pretended to be a wrestler in the crowd; he stiffed and sidelined a wrestler in another venue because him (New Jack) botched a move and didn't like being told on that.

That and the fact he actually killed several people due to him being a "bounty hunter" of some sorts.

He's just fucked up in the head, fun fact WWE was actually considering him being the one that "stabbed" Cena in the nightclub during his feud with Carlito when it ended up going to Jesus.

I don't believe in good or evil

I certainly think he's crazy though

New Jack is not a good guy. He's not a bad guy. He's... just a crazy guy.

who probably should be in jail

Didn't he get brain damaged when Vic Grimes fell on him?

Yeah he did.