I think there is a difference between a selling club and a club that sells. Semantics, I know, but bear with me a moment as I think the article has made a very valid point.
Prior to Moyes and even until the last two years, we were most definitely a selling club. We sold because we produced/found players of too high calibre to play for a mid-table/relegation battling club. Our sales were largely coerced by necessity (financial survival) or by the wage demands of the player. (Rooney being example #1).
Now, I believe, we have moved from being a selling club from which the big teams find new talent, to a club that sells. Let me give some idea to what that means for me. A club that sells is a smartly run club (and in our case out of financial necessity). A club that sells may, from time to time, choose to sell its prize (or one of it's prized) asset(s) in order to fund/make room for what the club sees as a net gain. For me the Lescott saga was and is a perfect example of this. Yes Lescott wanted to move for higher wages and yes Citeh's money was ridiculous, but could we have kept hold of Lescott and benched him til he changed his mind? Sure. We sold Lescott because we wanted to better our squad. The 3 players we bought with the Lescott sale are evidence that we benefited more (in pure football terms) from his departure than had he remained.
I think this is what the author of the article is trying to get at...and for me the way all clubs should be run. There are not an infinite number of quality footballers and even less positions on the first squad, so logically some players (even good ones) need to be sold to make room for changes and improvements. All clubs sell, but some choose to while others are coerced.