If users use this in bad reasons then its possible but proclaiming that bitcoin is a criminal tool is a bit overwhelming since we dont know if its true or not. We need proof or evidence if that situation truly exists. With that we dont need to panic because as long as good users is more than the selfish ones then its next to impossible that bitcoin is a criminal tool.
"Bitcoin is a terrorist tool because some criminals may use it"
Then so is the food we eat, because other criminals may eat it too. So are the roads, because they drive on it too. So is a currency in your pocket because a criminal may have touched it.