I have seen some news regarding hackers, terrorists, and other criminals using bitcoin for illegal trades.
How the police can find about these transactions?
Even if is hard to track illegal transactions, I don't think that Bitcoin can be a danger to society, since the problem is the society and its people.
Since the beginning of the internet this is happening ( the bad people committing crimes) and no one is willing to shutdown internet because of that, so in that matters Bitcoin should be equivalent. I think those illegal transaction are one of the reasons some governments and the media are trying to depreciate bitcoin, but the problem is not Crypto/blockchain or Bitcoin, is just the society.
Well those things makes bad publicity for Bitcoin in general because people are making those things come into reality that makes other people turn into thinking that Bitcoin do really have that bad effect in the society which must not already be blamed on Bitcoin because Bitcoin was not the major problem here but the human behavior because we are the ones who have been using it for either a bad or a good thing. That was really true that with the rise of technology, there is also a technological improvement happening within criminalities which already involve usage of technology to fool other people that was a sad truth because the reputation of Bitcoin was being put into danger.