Why were civilians not evacuated first in Afghanistan before American Troops were removed from most of the country ?

Having served on MSG duty in sub-Saharan Africa:
1) People tend to think "I'll be OK" until it is absolutely unequivocally clear they are NOT OK! Usually after blood has been spilled, there has been sexual assault, or loved ones have been dragged away screaming.
2) You can advise/order people to leave NOW, all you want. Some simply will not go.
3) Sometimes the evacuation order itself is the spark that ignites the powder keg.

This really isn’t a Rubik’s cube, no reason to overthink it. Simply, we didn’t think the Afghan military would just quit and the Afghan government would correspondingly collapse.
We intended to keep our civilians, diplomats, contractors, etc in country because we expected the Afghan government to keep itself going for at least a little while.

If that doesn’t make sense to anyone, please explain.