American cult groups

Some few years ago I spent the best part of a year touring North Dakota, Wyoming, Montana and Idaho.  I frequently came across groups of people who had bowed out of society to live and run their own alternative lifestyles. Amongst other things, they didn't pay taxes.  Generally speaking they were OK types, but some were clearly "away with the fairies" and disconnected from society in more ways than just a few.  Although at the time I never felt concerned for my safety, a lot of Americans have since told me that I was running great personal risk in involving myself with fringe groups such as these.  Do they still survive in significant numbers, or has the US national or state governments oppressed them out of existence ?