I guess OP rather means that it shouldn't be really taxed because money itself isn't taxed. Unless you have to pay tax on wealth, but that is a different story. If I understand him correctly he is a proponent of Bitcoin being used on a daily basis without running into taxation issues because you buy a bagel with your crypto and now actually triggered an event that now entails an event which is subject to taxation.
That is one of the biggest problems cryptocurrencies still face when it comes to using them on a daily basis. It doesn't matter whether you use a card or whatever, in almost any case you have to pay tax or realize a loss by using your cryptocurrencies.