You are require to pay taxes for the government to support its constituents also especially in those industrial country where the government rely on taxes for infrastructures.
Tax is playing a very big role in any economy if the people stop paying tax so a country can be destroyed so its very important to pay tax and Im sure in any civilized nation tax is number one priority for them because country is same like house and no one want to destroyed it house and I hope bitcoin and its users will also start to pay tax if bitcoin become regulate in all countries so it will help more to countries and Im sure bitcoin will end world poverty.