He doesn't do much harm to Newcastle that I can see. He gave the club a huge interest-free loan (£129m I think) and gets some free advertising for Sports Direct in return. Apparently no one has ever put an alternative offer to them that would be more financially beneficial to Newcastle, so the situation persists. Other than that he just keeps player spending in line with income and stays within FFP limits. Newcastle fans hate him because he won't plow millions into the club for established star players, and because his reorganisation of the management structure led to Kevin Keegan's departure. The reality of that particular situation was that Keegan was a chequebook manager who wasn't so great on the tactical side of the game, and he quit because Ashley was taking control of that chequebook away from him.