What made the involvement of cryptocurrency with crimes is that, the anonymity attained from using cryptocurrency secures the disclosure of one's information to its system only. You might ask "What information?" not personal infos, only the time,date and amount that is why it is commonly used to pay for international crimes like smuggling of goods obviously to avoid being caught by the authority. There is nothing for us to do with it since the system was born decentralized. But a middle-man (exchanges) can interfere someone elses action under their hand, they have the right to freeze and investigate when something unusual happen especially when talking about long numbers.
That is right, and that is not the only problem, there are also these scams. But I think these problem is not the fault of the system too but our fault as investors and users. If we have enough knowledge about how things work, we don't need to worry about being scammed or being tricked. We should be really careful since we are dealing with crypto currencies.
