A good cult will have a long asymptomatic period where you still seem pretty normal and go out in public to spread the news.

Scientology really nails this one by couching everything in sort of vague self-empowerment mystic pseudoscience prevalent in the places where it's popular. (Florida and California)

Most religious cults achieve this by wrapping everything in a [POPULAR RELIGION IN THE AREA] outer coating that allows people to be deflected until they are READY TO SEE THE LIGHT.

This serves another useful purpose, by making you sink some cost into the reveal, you're more likely to go along with it, but for the purpose of this thread let's focus on the "hiding in plain sight" aspect.