Many (most?) governments don't quite know how to react and deal with Bitcoin and cryptocurrencies. They are concerned these coins will pose an increasingly significant challenge to their currencies - the latter they can control. But not with cryptos. The total value of BTC etc. may be just a fraction of fiat currencies of many countries right now. However, governments know it will definitely increase.

Another reason is that governments don't know yet how to get a cut from their citizens' involvement and usage of cryptos. If there's some mechanism where these governments could get a cut of the action, I'd bet they will be a lot more supportive. Like with the "stamp tax" and such imposed on each transaction in the stock market.

I believe the more forward-looking governments will find ways to accommodate and coexist with cryptos. Provided they can collect some tax on it.