Cult is a strong word that has a fairly defined definition. I think it’s being used out of context here, unless we move into leader worship.
In US high schools, you could raise your GPA by community service/volunteerism. It eventually became basically mandatory if you wanted to get into a top school. At that point is it volunteer? Hmmm.
Encouraging volunteerism and charity is a good thing. Making it mandatory is contrary to volunteerism or charity. Springing folks without prior disclosure is really unfair. At that point folks simply have a choice. Stay or go. Can you sue at that point for 5 years of dues? I suppose you can sue for most everything.