Because it will collapse at some point as a result of basic mathematics and, up until the point it does, those who participate are seeking to ensure that they get given a share of somebody else's money by the ponzi scam operators as a reward for their assistance in helping the ponzi to function as needed, namely, through their participation.

So, you have both a scam and behaviour from participants which proves they don't give a shit where their 'profit' is coming from.

That is the definition of an untrustworthy person, QS.