Makes no sense. How can you treat a barter exchange as income? If $600 worth of sex between two individuals took place, that logic leads to a total of $1,200 dollars taxed. What happens in case of a threesome, or an orgy? One orgy.
By the same token, if I am selling potatoes for US dollars, those dollars are my taxable income, but so are the buyer's potatoes. Does the buyer pay income tax on the value of potatoes? It's an exchange.