Because until now bitcoin creator still unknown maybe they still have possibility the government create a bitcoin but the question is what country?
Because some of the government want to ban bitcoin to their country maybe they did not know that government of other country who create bitcoin. But all of that is still a big question and until now No answer until we find out the real Satoshi Nakamoto.
More than 10 years back who created the Bitcoin till now we don't know, but governments always want to control the money which is maintained by them. So that's why most of the governments don't want to show their interest in Bitcoin because no government control authorities are not maintaining it.