Tax free earnings are explicitly specified part of tax law.
All avoidance is part of the tax law. You can never legally evade taxes nor illegally avoid them. The difference IS important, even if you wish it weren't.
As for those two words they have the same meaning as far as normal people are concerned.
Ignorant people may feel that they have the same meaning, but they don't. And there's nothing normal about lauding emotion over reason. Most animals display more emotion than reason - that is what seperates us from them. Why the very law you herald is designed to weigh reason over emotion.