Some people think that bitcoin is a scam as a result of their encounters with fraudulent activities using bitcoin, and sometimes, bitcoin platforms.  No matter how genuine bitcoin as a currency is, frequent encounter of scam with it or its platform changed those people's mind to consider it as a total scam without distinguishing bitcoin and scam.  For example,  for the fact that pound or dollar is a genuine currency, does not mean that scammers can not use them for scam, likewise bitcoin.