There are usually more factors leading to that though. Maybe there is a strong teammate behind who you don't want to drag to the finish (I guess Brändle is actually one of the reasons they decided not to chase hard but not chasing because you are afraid of Brändle? That doesn't sound very smart to me either), maybe there is a really strong guy in the group who would easily win if everyone does the same workload. So often we've seen groups with Sagan getting attacked, Sagan then not wanting to do all the chasing, and the others not wanting to help Sagan.
But this was different. You had a group of fairly evenly matched riders who all would have benefited from working to catch Dowsett yet they gifted him like half a minute on the kilometre before the final climb alone. That's inexcusable.
And considering they gained half a minute on Dowsett on the climb alone it's also not like this was a hopeless cause. They had a good chance to catch him but decided to rather look at each other.