Usually it is due to ignorance, they do not know the important information about Bitcoin. I try to explain what Bitcoin is all about it, how it works and what the advantage is. Sometimes they change their minds, sometimes they do not, but in the end everyone has the right to their own opinions
 They will face so many economic innovations that become scam. bitcoins with such scam projects.
There are many people still can not accept bitcoin as a new technology and this but slowly I will explain to you that bitcoin is the good thing that we can do.