Skinwalkers are often referred to as being similiar to "hit men". According to local lore, one can obtain the services of a skinwalker to target an enemy. What this person has done to get this sort of treatment, it all depends. It could be jealousy, hatred, politics--anything you can think of that is bad.
According to my husband, it started with his grandfather. His grandfather was the head of the family and all land went to him. Keep in mind that land that one can call their own is very scarce on the reservation. Most families have nothing. So, he was someone to be envied and perhaps even angry with. He also had a very interesting perspective in regards to skinwalkers, even as a young boy. He had no fear of them whatsoever (just a healthy dose of respect) and had, as a result, numerous interesting encounters with them. What could've initially started out as somebody "hiring" skinwalkers to bring him ill probably turned into something entirely different. A few of his sons still live on the ranch and he raised them to perceive skinwalkers in the same way. They don't cower inside their house. When they get visited, they go out, ready for a fight. I suspect this is a reaction that skinwalkers cannot afford to have happen. The ranch is still in the family's hands as well and it has become a significant political issue over the past couple years. There is alot of resentment building in the area. The family also had alot of personal success over the years and that could incur alot of jealousy.
These are just a couple of the possibilities. I think the persistence has mostly been that my husband's grandfather did not perceive them as being supernatural or even possessing magical abilities. He saw them as human. At least, that's my interpretation. Why skinwalkers plague the family, one can only guess. I guess we'd have to ask them, lol.
Stephanie
In every man there is something wherein I may learn of him, and in that I am his pupil.--Ralph Waldo Emerson