What a bunch of short-sighted, pea-brained morons. Rather than trying to figure out how to make good use of her ability they just got rid of her. She could single-handedly dig a tunnel through a mountain or a gigantic moat around her village. She could be a demolition machine.
I suppose she could not control her own ability for some time after birth. She destroyed her mother as she was born after all.
Makes you wonder how she even stayed alive until she realize and could control her ability since babies and toddlers would touch anything, including themselves.
How she could even eat during that period was another issue.
Though I suppose her father could just hold her whole arms down while feeding her.
Those are beside the point though, these people probably was scared shitless of her and thought she was some sadistic bastard who got a kick out of hurting her own mother and father. So they would not think of putting her to use and making her do things might even make her turn on them.
The details on if they ever thought about how mistreating her may turn her against them too is unclear and probably would not cross the author's mind or the actual people in that situation, really.
Yes, the world is that cold a place.
Once you are alienated, expecting anything from those who alienated you is just futile.
After all, those who resorted to such measures are likely to not be rational, let alone caplable of thinking how to put one's ability to good use.