Perhaps if you are saying attacks of politicians switching parties, which I could see. But I don't think I've ever heard of republicans talking about exrepublicans or democrats talking about exdemocrats. I personally have switched from voting republican to voting democrat. It's not something my family really cares about and I still have good relations with them even though a number of them are pretty MAGA.
Cults will actually have lessons and classes about the evils of ex members. Someone brought up JWs and that's a pretty good example of what I'm thinking of.
* 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.