Manipulation is always there and I think even if the government would show this as not truly a manipulation they can show this to the public as part of the law, but I guess the government would not give any law if they didn't see any wrong things about it, I guess you can surely own something that is your right, for example, you can own a gun with a proper paper license but that very gun is used to killing someone or used illegally I guess the government will do a proper action about this they may implement a gun ban, Then even if a person would have proper property with the gun it can still be confiscated, I guess the government will lead to something like this if Bitcoin or other cryptocurrencies would be used illegally.
There are still countries that have never allowed guns to be legalized, a bad thing doesn't need to happen for the item to be banned (eg, some governments are being smart by banning guns early on), and this seems to be similar for some countries and Bitcoin.
Most countries haven't seen a lot of Bitcoin used, but they will still ban it due to their misguided views about most bitcoin users being criminals - which I'm not saying is good, but we can also do nothing about it.
if a coin is decentralized then banning it is useless.
Still it is possible to ban Blockstream not bitcoin.
That's true, they can't fully "ban" bitcoin, because there are VPNs, accessing your wallets via the tor network, but they can issue large penalities and also make sure it'll never be mainstream in your country, which is still a huge negative.