"Fairness" should have nothing to do with the law.
What you consider fair and what I consider fair are probably not even in the same ballpark. When it comes to a law, any law, it should be "equitable". That is, the law should apply to everyone equally and under no circumstance should two people be treated differently by it. If they are then the law in question should be struck down as unconstitutional.
If one person is taxed at 10% and another one is taxed at 50% then the tax law isn't equitable, as such, it should be unconstitutional. Let the law apply to everyone the same or to none at all.