They do it silently.. remember the ad ban by google, twitter and facebook? How many time in the past we heard about state interference from these companies. NSA, spying etc is just the top of the iceberg. They try to silently hide cryptos... Tell people it's dangerous (e.g. fed announcements). But when they will introduce their own "official" cryptocurrencies they will tell people that's the real deal, cause these chains they can fully control. bitcoin they can't.
I think also it's a matter of your citizenship. If you live in China, the government bans it. If you live in Europe, they can't, cause official they are "democratic" :DD