-snip-
1. Lack of knowledge about Bitcoins, uneducate People only saw the negative sides of Bitcoins.
2. Some of them say negative feedback because of their experience on some sites about Bitcoins, because now a days Bitcoin are popular but there are many site will scam you if you are spontaneous to invest in not trusted sites.
1. They are following the wrong media. I am pretty much sure those people that "saw the negative sides of bitcoin" are the ones that read random articles posted on facebook and twitter. They gave little to no effort to understand or verify the claims made by those articles.
2.Lol, if they fall for those stupid scams and then start calling bitcoin a scam without learning from their mistakes, then they should never enter the crypto market.