Earlier quoted context omitted.
Aren't those clearly frauds for the people participating, but as businesses they're just somehow structured in a way to be sound investments for those on the outside?
If those were frauds, there would be ton of lawsuits by now given their history. It may or may not be immoral for participants, but illegality is a much higher bar.
So much so that both Herbalife and Amway have been under numerous consent decrees with the US government for decades [1][2].
[1] https://www.ftc.gov/news-events/news/press-releases/2016/07/...
[2] https://www.govinfo.gov/content/pkg/FR-1994-03-23/html/94-67...