> I don't think picking various commodities as the "true" measure of what is "valuable" is a useful exercise.

No one said that a commodity is a "true" measure of value. A commenter simply said that it is often a useful proxy. It is something that is useful to do to understand specific trade patterns.

> I suggest you put your wisdom to use on the various markets that are set up for this purpose instead of arguing with me.

I did not claim any wisdom on the subject. And I suspect you are deflecting attention from the fact that you are not arguing in good faith