Is he doing something that is illegal ingame? So if he wants to be online 24/7, isn't that his choice? If he wants to sell something on the AH, isn't that his choice? If he wants to do it cheaper than everyoine else, isn't that his choice?
If he want o give away his gold, isn't that his choice?
He puts in time, effort to do this; it is the way he wants to play wow. If the others wants to sell, well then they should put in more effort, more time. Simple, is it not?
If you think he is botting, then he should be reported. If so, then Blizzard will take the necesaary actions. If not, well then.. it is a free market.