idk how would they hack bitcoin? its like asking to hack every computer in the world. its nearly impossible , they called it decentralize for a reason ^_^
That is not what the OP is telling, if you look at the bitcoin network majority of the hash rate comes from China and the government can take control over these mining farms and control the entire bitcoin network, what you do not understand is that bitcoin is decentralized in nature but majority of the hashing farms are centralized and if you control these major mining farms you can control the bitcoin network.