There were many people that ISIS hated, including Afghans leaving the country, milling about with suitcases and backpacks. It was impossible to set up a perimeter with people coming through all the time.
Bring them home. August 31, 2021 date of leaving. SET UP A PERIMETER. If is causes problems in processing then the processing will have to be done at distant locations.
Kabul Airport will never be an asset to Afghanistan again. There will be a lot of destruction because of the new civil war between ISIS and the Taliban. Pakistan should close its borders to prevent migration of jihadists.