So yeah, what most everyone else has said. So long as you are not conducting these transactions for profit, then you are conducting private party sales. Same concept could be applied to cars or lawn mowers. Technically as long as you are paying the appropriate taxes you're good to go.

Secondly.. why the hell are you even engaging in said debate with a obvious dolt on the Errornet? Just don't bother engaging with him. Or asking what legal references he's drawing from to support his stance and judgment.