Disagreement is too often viewed as dissention. I see Generals writing books after retirement on why "things" didn't work but you see very few that voice it while in uniform. If you are going to stand up for something I would think when you are wearing stars is the time to do it. But maybe they got to that point because they never did stand up.

General Mattis has already answered this question for us. The quote that I’m referencing has been posted on the forum a few times; here it is if you haven’t seen it.

If you are always on the hunt for complacency, argues Mattis, you will reward risk-takers, and people who thrive in uncertainty. "Take the mavericks in your service," he tells new officers, "the ones that wear rumpled uniforms and look like a bag of mud but whose ideas are so offsetting that they actually upset the people in the bureaucracy. One of your primary jobs is to take the risk and protect these people, because if they are not nurtured in your service, the enemy will bring their contrary ideas to you.

Do you think he'd charge young officers with protecting the true mavericks in the group if they didn't need to be guarded?

Here’s a 4 star general, the former commander of CENTCOM no less, imploring his Marines to take risks to protect the very people who he knows will buck the system. It's pretty obvious that if the military wanted a wide breadth of insight and input from its people, you wouldn't have a man of General Mattis' caliber issuing such a grave warning.

Articles with the quote:

Slate: Mattis 1

Slate: Mattis 2