I think that's true of just darn near everything. People are tribal and tend to get uncomfortable when people around them change:

* Their political parties

* Their religions

* Their diets (meat => vegan, or vice versa)

* Their music

* Their computer OS

None of those compare to cult shunning, which is more systematic and absolute. I mentioned in another comment that my parents were sad when I stopped going to church. That's got nothing on having one's entire family and support groups ceasing to publicly acknowledge their existence.