Many businesses have characteristics of ponzi schemes without being ponzi schemes. You're right that there is a bright line distinction in some places (i.e., if there is actually a fraud), but why is it wrong to bring up that there is a resemblance in some way?
I'd probably also note that the JOBS act, while it does give additional opportunity, doesn't do much for your ability to assess an opportunity. My colleague Jim Allen gives a good overview:
http://blogs.cfainstitute.org/marketintegrity/2012/09/07/job...