Earlier quoted context omitted.
What the US should do now in Iraq is learn some restraint, diplomacy, and humility. In other words, we should learn the lessons everybody but the military had already learned from Vietnam.
It might be a surprise to you, but it is the military who learned the most from Vietnam. It is the American public and our politicians who seem to have learned the least. The military is simply doing its job when presented with a task, whether it was spawned out of noble intentions or kneejerk reactionism. They know that they must be careful in pursuing anything that looks vaguely like a target, because the sentiment…
That was presented as a defense of My Lai and was a not successful argument.
The military is achieving far more value
You're going to need to quantify this statement, because from this distance it doesn't look like much is being achieved at all. Yemen has fallen to the rebels and ISIS still hold much of northern Iraq.
answers like "don't invade other countries" are pretty worthless.
Absolutely not! It's a simple, clear, actionable, moral rule. It's also a core principle of international law. I'm not sure why this is so much of a problem.