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 i also think that government are afraid from bitcoin and they doesn't want to accept this currency but actually bitcoin is a most beneficial currency for everyone and that's why government should improve this currency for their citizen because everyone wants some extra income in their life and that's why bitcoin can make everything possible.