The truth is that people will always complain. Not even Jesus who gave his life for us escaped humans grumble. Many people have said that Bitcoin is used for negative things like money embezzlement, tax evasion, fraud and scams, drug trade, and many others which has always needed a way to wipe it's footprint. But when you think of these things, all of them have been here before the creation of Bitcoin. Bitcoin is just a tool like a knife; one can use it to cut something loose while another can use it to st*b someone. It all depends on what for and how it is used - it creates no direct cause!