- Why would they give him a hook for a hand if they intended to kill him anyways?
- Because they were just torturing him for the hell of it.
- They probably didn't give him one. The urban legend itself did. It's a story of a one-handed killer. Of course he must have a hook in the other hand.
- The flashback leads us more to believe it was an in-the-moment torture. To chop off a hand and then stick a metal object up into the flesh would have been highly painful. It's just no one at the time wondered "what if he comes back as a homicidal ghost with that hook".
- Why would the Candyman stage his mutilations in such a way that it seems that someone else did it? I mean his ability to exist hinges on people believing he is real, so why doesn't he just make a grand demonstration? Kill someone when they are in the open? I mean it's clear he is patient and doesn't need to kill the instant he is summoned.
- Because if his existence is confirmed, people might become a lot less cavalier about summoning him.