Somebody mentioned it earlier but it still is ASO's game or playground and they can see fit on how they want to run the game or not. ASO, in a business sense, have a "product" and want to control it's image it in whatever means they feel that they should - right or wrong. Thus far they have kept people tuning in to their event in this modern media-rich world. Or - if this action is just a case of cycling politics which I am sure that some part of this action is represented by, then they can see fit to take that risk as well. Look at the publicity they have received today alone. Some news is better than no news. A lot of people love Le Tour for it's tradition, not remembering the particular riders or teams who were excluded - you find the stories within the race whoever participates. There was an article written last year that showed that it is the pursuit of the yellow jersey not in-fact the pursuers that "Le Tour" sells.
Second, every year there is some foreshadowing of what to expect during the summer for cycling. Two year's ago there was information regarding Operation Puerto and Basso and Ulrich. Last year it was hints of Rasmussen missing controls. I believe that with Operation Puerto re-opening along with UCI and WADA active in pursuing riders there will be a major announcement (read very bad news) surrounding either Contador, Bruyneel or Discovery. I just think that ASO has had a little bit of a head's up or is more in the loop this year or has their hand's in the game themselves surrounding news to come out.
Finally, don't you think that any smart cyclist or agent of a cyclist like Contador or Leipheimer or especially Klodi would include in their contract a clause that allows for them to take appropriate actions if they were not in the the Tour? That is, if they wanted to be. Doing well in the Tour pays financial dividends to these riders. Non-participation could seriously hampers their financial well-being. Or they are just happy taking the money this year and sitting out of most of the races? The big riders are being well compensated so why not have a quiet year this year and take the money and wait until next year. Nobody is accusing them of seriously doping yet. Just being on the wrong team at the wrong time, much like Unibet.