The kind of people we have in government are people who always want to fight for their selfish interests, anything that will surely benefit them. If it's something good that has to with better development for humanity as far as it won't benefit them they will surely go against it.
The reason government won't accept bitcoin is not because it is a decentralized currency, it is because they won't be able to print it like they print fiat to steal as much as they can .
If bitcoin is something the government can manipulate to steal public fund they would accept it even before now without any delay.
You sure have a good point though, coming from a country where the government is so corrupt to the extent that they steal even funds belonging to displaced persons. Orphanages, funds kept to cater for the less privileged people In the society, I can really understand when you state this reason as one of the reasons why they won't allow the use of bitcoin in the society..
If bitcoin and made a legal tender and the masses move to transacting in bitcoin, the government will automatically lose the grip they have in their citizens through fiat currency , power will be taken away from them and passed back to the masses which is where it belonged to in the first place..
So, bitcoin is indeed, a threat to most of the government of the world, but the good news is that, even at that, they still can not stop bitcoin.