It really depends on the law; its universally accepted that stealing is bad, Bitcoin is legal in one country and illegal in another so its not universally accepted that holding Bitcoin is bad; its just the government that makes it look that way.
I don't think you are committing a sin, but you are violating a law in your government that makes it bad for their citizens, so its on your discrepancy if you think that you are violating then don't hold if you believe on Bitcoin and you think you have future holding it, then go hold, just don't get caught holding, its for everyone's preferences there is no one rule.
Truly depends on the countries regulation if they allow or discourage their people to use bitcoin. If there's massive crackdown implemented and government says or declare that bitcoin is illegal then automatically you violate the law by using or acquiring it. Not following government order is actually a direct disobedience and you commit a sin on the government only.
But to become a bad citizen for that matter, I guess its not since for sure its never so bad to used bitcoin. Its just there are regulators didn't understand how to use it since maybe there's certain conflict of interest that they are protecting and they cannot take advantage with bitcoin to gain something that's why some of them discourage or totally ban this asset.