Your last paragraph is true - Ultimately it's up to the team to decide what is better value a possible stage win or a possible 6 to 10 position - Don't forget that Mollema is also riding the TDF.I disagree. For him -- absent crashes, illness etc -- it's a matter of priorities. If he said, I'm going to target top 10 in the TdF, that should be a piece of cake. All he has to do is TT decently and follow wheels without attacking. He may not be in the very top rung of GT riders right now -- but at least half of them are Sky or Jumbo domestiques this year who at some point will have to sacrifice themselves.
Somewhere there's a thread about highest placed GT riders who had the worst "best" stage finish, i.e., I think it's very possible to get a top 10 finish without ever finishing in the top 10 of a stage.