Uhhh it most certainly IS taxed, how do you figure 0%? I actually sold some BTC to purchase my Model 3 and got super lucky selling in December before the drop, but then had to pay short-term gains which was kinda painful.
He explained why his long-term capital gains are 0: Because his marginal tax rate is only 15%. I.e. he doesn't make enough money to have to pay taxes on long-term capital gains. (Short-term capital gains are a different category and are governed by different rules.)