Btc isnt a fraud nor ponzi as its a legit crypto currency that has real value and valuable to many. Maybe there are other tokens or ICO's who are fraudly using this tactics maybe thats the cause of the misinterpretation of lots in btc, people tend to generalize the meaning aside from single outing the token itself. Btc cant be a fraud unless everyone will stop buying and selling it or we can call trading in the market. Just do what you think is good