There is often a way to evade tax and Bitcoin is one of them, tax is not an concern in country, because people get little back from government so there is no need to do so, unless of course you want to go for political put up.
Taxes need to be paid, even if you are getting nothing in return. It is mandatory to pay the taxes. If you don't do that, then you will end up in jail. But there are legal loopholes out there, using which you can reduce the amount of taxes being paid. Or if you can afford, you can re-locate to another country, where the tax rates are quite low.