Your ethical argument is a bit weak. If society sees Bitcoin as a bad thing then there's no reason why they shouldn't slap a huge tax on any gross transaction, be it 34% or 340%. There are many ways to view cryptocurrencies in a bad light. It is a scheme that some claim seeks to subvert the fiat money systems that are controlled by these national tax authorities, so you can see why they would be upset. It is also, to a large extent, just gambling. Finally, it is a money system mainly used by organized criminals to launder money. In short there is no ethical argument against taxing it, any more than there is against US tax code for gambling (you cannot deduct a net gambling loss against your other income in USA).