because they haven't learned Bitcoin and it's still a new technology, they cannot have control of Bitcoin and they are very afraid money laundering, terrorist funding or fraud investments growing rapidly if Bitcoin remains. I think this has been discussed several times 
Yes this topic has been discussed many times and terrorist funding and fraud investment are just a lame excuse which is given by government as there were terrorist attack before the emergence of bitcoin and the real l\reason why they hate bitcoin is because they cannot control the money and they will lose the money which is under their control.