turkey3_scratch :
It is cultist behavior on a more professional, concealed level.
I don't really mean to defend political parties, but I would say that characterizing them as cults isn't generally very accurate. People & politicians typically belong to them for pragmatic reasons, which isn't something you can say about a cult. In cults, individuals sacrifice their own interests for the good of the collective, but you don't generally see politicians doing such things.
Certain politicians definitely have a cult of personality, however.
BTW, I'm also not a joiner. I might join something for my own interests, but I'm allergic to secret societies or anything where I'd have to be invited or otherwise voted in by the members.