Most countries haven't assessed it yet that they can tax bitcoin but it will come so why they aren't doing it, enjoy.
May I ask how old you are? I'm asking this because if you have ever paid tax, you know that there isn't anything in the world the government can't tax you for. Even if it concerns your shoelaces, taxation applies.
I however do believe that governments will rewrite certain areas of their tax brackets to make it easier for average joes to understand. Even the people buying and selling Bitcoin in 2011 we're legally obliged to pay tax.
Most of them probably didn't bother to pay tax, which is entirely up to them and perfectly understandable, but there is just no way to get around it. The government is everywhere with their taxes.
I've been a tax payer since then, all of my properties and even my salary were taxed. Yes, I know that thing where everything can be taxed by the gov't.
I'm saying that they are still in the stage of knowing the process and if they will adopt it or not. And a person that isn't sure of it has free will to file his income tax.
But as a law abiding citizen, we are obliged of doing so.