Bitcoin can not be managed by the government or any other agency, but the bitcoin can be manipulated by a party, so I am afraid that there will be a party who wants to play bitcoin by means of manipulation, if that happens, then it can destroy the economy of many people.
I agree that it would be very difficult if not impossible for a central authority to control bitcoin, but with mining concentration growing in China under Bitmain, the likelihood of a 51% attack increases, especially if China seizes their equipment under duress.