Not sure the logic here. What does BMC care if Froome takes pulls or not? I don't think BMC has any illusions of first. But they would like to beat the Kreuzingers, Ten Dams, and Fuglsangs of the world. And they're not doing that if they give all those guys 5 minutes for free.
When the split happened, Valverde had been dropped and 3rd, 4th, 5th, and 6th place overall made the front group. Kwiatowksi was 7th and really isn't seen as a big GC buy (not to mention he was not going to chase down Cavendish) and Quintana was 8th but had no teammates. So doesn't it make sense for the 9th, 10th, and 11th place guys to try and track down the guys ahead? What else are they going to do? Sit around and do nothing out of spite. What exactly are they saving their domestiques for? It makes more sense to work together and all pull, then to burn one team out (Sky) and then play a game of chicken to wait for the next guy to pull is. You'll loose less time all working from the get go.
Seems people are just upset because Froome could have lost more time and didn't. He didn't because it just so happens that Froome's interests and Katusha's and AG2r's interests alligned on this one. It happens.