It is humans fault why bitcoin is used for illegal activity. Bitcoin is open to all types that we can use. There's no doubt that even in the illegal terms it will be include in this kind of activity.
agree with you, it depends on every people wants to do with their bitcoin. I think there will be any illegal activity using bitcoin but I also believe that there are many people is using bitcoin for a good purpose. bitcoin give a chance for us for what we want to do and bitcoin also give an option to us and if we only use bitcoin for a good purpose then bitcoin will help us to reach our goals. I think we need to use bitcoin for good things only and don't ever try to use bitcoin with any illegal activity that could make us go to break any law.