They are free to believe what ever idiocy they choose.

You say this as if their beliefs are inconsequential, merely ideas in an abstract. This group is a predatory cult. It was recently publicly revealed that one of their members already killed themselves due to internal oppression. They regularly threaten people (including politicians) with violence and commit violence, and members have been charged and arrested for doing so. They're still doing it and growing in size. The law has shown itself ineffective at stopping them.

But ultimately, at the end of the day, this cult is organising with the explicit intent of exterminating people, including me. So, when do you believe I, or we, should stop them?