Because of the semi-anonymous nature of Bitcoin, its used in ransomware attacks. Hackers breach networks and hold them hostage until payment is made to them. Hospitals and schools have been victims of these types of attacks. However, unlike cash, which was favored by thieves in the past, Bitcoin always leaves a trail in the blockchain that investigators can follow.
there are so many events that ask people to submit bitcoin as a condition for release. I think this is a detrimental thing if bitcoin is used to blackmail people and this is a negative thing for those who use bitcoin.
of course it is people who are irresponsible and abuse bitcoin so many people say bitcoin is not good. it is very difficult to get rid of bad people like that from bitcoin because bitcoin is anonymous so that it can be used by everyone in a single form.