You clearly don't.
Lol, you are so exquisitely dumb.
It isn't me contradicting your assertion, it is a statement from the very same links you posted.
https://en.wikipedia.org/wiki/Ponzi_scheme
http://www.acfe.com/ponzi-schemes.aspx (Ponzi Schemes Versus Illegal Pyramid Schemes )
Judging by your attempt to claim there was a way to make an illegal ponzi not be illegal you obviously did not understand the content of those links.
Being the very observant person that you are, have you tried ctrl+F to search for the word "illegal" on the first two sources?
And I still assert that there does not exist a service for which it can be established 100% that all participants would fully understand what they were sending money to. These reputable services merely have satisfied all the current demands up to date. It does not mean that they could not, in theory, scam their users.