Bitcoin cannot prevent crime. Actually, it is one of the things that a criminal uses. According to what I've read in the past, bitcoin is widely use in the Deeo Web because many illegal activities were done and the mode of payment is via bitcoin. One of the characteristics of bitcoin is that you can use it anonymously. The criminals' identity can be hidden when using bitcoin as a mode of payment in their illegal activities.
The way you put it here, it seems that instead of blaming the people that abuse Bitcoin for whatever shady purposes, it's Bitcoin that is receiving your part of the blame. It doesn't work like that. Bitcoin is nothing more than a tool, where people are reponsible for how they make use of Bitcoin as tool. There is a general saying;
Blame the people and not the tool.
Other than that, people often take the 'anonymity' aspect of Bitcoin a bit too serious. There are dumb people just buying Bitcoin from whatever exchange they are fully verified at, where after that they spend these coins to buy drugs or whatever other illegal goods. From the moment the coins are withdrawn from the said exchange, the exchange in question can follow every single step you set. You can be easily linked to the purchase of illegal goods, where in some cases the exchange can even play all this precious information to the government in case they are forced to do so. In order to avoid all these problems, you should run your coins through a mixer.
