In my opinion many countries fear to support bitcoin is they think all the transaction of their citizens will go in digital even with out any knowledge of the government's and to their country this will cause the damage to government plans But they have to think other side of the coin that people's life style will grow in a standard of economical high in which the government will gain directly and indirectly.
They will never take the side of the people, once a government is formed they stop thinking about the well being of their citizens and those that are in the system only care about how to keep their privileges no matter what, so something like bitcoin is a threat to them because if bitcoin becomes the main currency of the world then governments will have to get smaller and they will lose their jobs.