We all certainly know there are a lot of people out there who hate bitcoin not only the government and banks, in fact a number of politicians also participate in aggravating the atmosphere with their skeptical tone. However if we pay close attention, in fact they don't understand the benefits and the positive meaning of cryptocurrency, let alone bitcoin.
Ponzi schemes are fraudulent acts carried out by unscrupulous third parties. By their cruelty, they have damaged the image and popularity of bitcoin so bitcoin in Cap as its only medium or tool for fraud with Ponzi scheme style. It feels what they accuse is unethical.