I can't imagine what, who and why something
could 'forbid' a conscious and unconstrained person from allowing or denying themselves an action.
It seems to me that what a person is like will dictate how they will act. For example, I can't imagine someone who would hit a child or drive while drunk suddenly having qualms about trying to hurt the neighbour with 'magic'.
I do wonder something , though.
If a person believes they can take a life with a curse, and if they think their curse DOES take someone's life, why wouldn't someone just take the 'cursed' person's life the mundane way? Murder is murder, isn't it? After all, one could never
really know if they caused someone's demise with magic. Wouldn't it be better to stick in the blade and give it good upward thrust, watch the person's mouth fill with blood and the light of life fade from their eyes? Then one could be sure that THEY, they themselves, killed someone.
What about mistakes? Say you see a hated neighbour take out their trash and notice some hair clippings ( if one uses this type of 'magic'). So you grab some, get out the poppet or curse means of choice and 'magically' create their death. The next day, the neighbours kid sporting his/her new hair cut runs out into the road and is hit by a car and killed. Hmmm. Not much satisfaction there.
As JohnOdin pointed out, everyone has a 'moral compass'. I can't see why 'magic' would fall outside of it for anyone, indeed, I don't see how it
could. We are who we are and will act accordingly.
I think the answer to why someone would hide behind a hex or curse is so as not to have to pay the piper . That's just my opinion. It's a way of feeling empowered and in control without the messy details of actual confrontation. Again, not very satisfying and really, without proof that our actions did something, without 'power'.
I can think of very few life situations which cannot be dealt with 'in person' . Of course, I'm not a vengeful type . By allowing myself to carry around a lot of hate and ill-will, I feel I am indeed allowing someone to control ME. If it is someone I don't like, that just cubes the effect of not wanting them to have any emotional power over me.
If someone hurt someone I loved, hurting them back will not remove the original hurt. What's the point except to feel one has done something, anything to feel the control we all need to feel - the control of our own lives, the feeling that we can control those things which may hurt those we love and like, our strength and our identity?
We will do what we will do. I'm not so sanguine in my ability to bend the occurrences in the universe that something I will do will pin-point with laser permission the object of my concern and not have rebound effects, even if those effects are the hurt and devastation of the innocent family members of someone I decided I had the RIGHT to hurt. With my 'magic'. With a knife. With ill-will.
To judge others, one must have ALL the facts, not just those effecting you. Are people so sure of their own 'rightness' in things? I envy that. Also, if someone is actively hurting someone I love, I'm not going to walk away and take the time to construct some kind of 'curse', I think direct action is called for. I'd rather not be late to help someone

.
Still, imagining 'vengence' scenario's can be a healthy way to let off internal turmoil. Acting on something? If one thinks they should, then do so. In my book though, it doesn't count if I want them to know it comes from me and I don't let them see that. But again, I just can't care enough about toxic people to try and 'fix' them - I'd rather just erase them from my life, I'd rather walk away.
Marto