Families have split apart for centuries, with or without religion as a crutch to aid and abet those rifts. People have fallings-out, and stop speaking to each other for decades. Children don't know their cousins or grandparents or aunts and uncles because of it.
It happened in my family before the JWs became a factor, and being JWs made it easier to excuse the creation of rifts (the old "persecution" routine). I have cousins, second-cousins and beyond that I have never met due to ancient family disputes that nobody quite remembers why they happened. It had nothing to do with the JWs. But once my family became JWs, new rifts were created, because of the clash of ideologies and the JW intolerance of others' points of view.
I think some families are prone to carry an intolerant spirit from one generation to the next. They learn that is the way to deal with conflict... by getting rid of the person (disowning them) and the conflict simultaneously. It isn't any less painful than being DFd.
What I would like to see is the broadening of the definition of "hate crimes" to include the various forms that bullying takes - including the use of social exclusion, rumor mongering (slander/ libel/ defamation) - and requiring family mediation, particularly where children are involved. If intolerance is a learned behaviour, then it can be unlearned, and tolerance and acceptance can be learned in its place.
I have never been able to figure out why my not attending the KH seems like such a threat to my JW family members... it is only the intolerance that they have learned that would compel them to view me in that manner.