These transactions would be half money laundering only if the buyers only came from illegal activities and they were avoiding deposit in a typical bank. It's not laundering by the author as he is not involved or aware of the buyers' money's providence. I don't see how it would be money laundering more than say, buying $3000 of gold from a local gold and silver shop.
I'm hardly an expert in... Anything, though. If you care to explain that would be lovely.