Not necessarily true... again it depends on the tax rules that apply to you. In the UK you can buy Gold Britannia coins and Sovereigns which is Capital Gains Tax (CGT) exempt because of a loophole where British Legal currency (which the gold coins are) is exempt from CGT.
Well the commenter didn't say they were speaking from a US perspective and I wanted to emphasise that it's not the case for everyone. While HN definitely has a US slant, there are still a great deal of HN readers from around the world that I wouldn't want to be given the wrong impression.
Second, forex traders (and gold owners) have to pay capital gains taxes on any gains.
So, what is your point?