As long as its moving in predictable patterns for them it is profitable. Fake volumes is something these exchanges should be getting smacked for but no one seems to be bothered by it that I have seen when this topic is brought up.
We shouldnt ignore that though..
I saw a week ago someone pointed out bitcoinwisdom show fake volumes at random spurts at a time.
But it could just be the person reading the chart wrong.. I dont know. Id link it here if I can find it again.