It's not opinion, it's historical fact of mistakes made. There's only those that won't admit them.

When people like Shinseki, Zinni, Schwarzkopf, et al express opinion, that is based on years and years of military study, experience, and practical anecdotes. Their opinion cannot be dismissed as purely speculative. Compare that to the resume of the current DefSec and his minions who have virtually nill time in uniform.

If indeed we "offered the current admin full support," it would not have had any bearing on the outcome or repercussions of what has happened - other than the public burying its head in the sand and accepting mediocrity from its leaders. The war would not have gone any better, yet the administration would have had an easier time spewing its propaganda.