Many economists don't agree though. If you care about economic success of the country, the goal isn't 'collect as many taxes as possible'. The goal is to make the citizens wealthier in real terms.
Effort your citizens put into tax collection is 'dead weight', and doesn't contribute to exports etc. However, effort your citizens put into trade that (for various reasons) ends up under-taxed, usually does add to the economic wellbeing of citizens.
Therefore, it's only necessary to collect mostly-correct taxes from most citizens, if doing so let's you redirect labour from tax collection into other work.
Is it unfair? Yes. But it's still good economic policy.