And starting to force civilians out, publicly showing that this was being done would have invited more attacks. Even with thousands of troops there and an agreement to do it a certain way, they couldn't keep all attacks from happening. If they would have been trying to take civilians out of Baghram, that would have been even worse (from what people who were there have said).
Hindsight gives everyone 20/20 vision and makes everyone believe they know who it "should have been done".
Now, there are definitely some things I disagreed with too. For one, no one should have been allowed to fly from the US to Afghanistan after May if not really even after January. All visas allowing such passage should have been revoked. That would have cut down on how many were there. And efforts should have been made to identify and contact every single American in Afghanistan to emphasize that we were leaving, they needed to leave then, not wait. We also should have worked harder at identifying those Afghan allies, those who worked with us, who we knew would need protection to get them out too, to at least identify them and their needs, what plans could work to get them out and started the processing if it hadn't already been started or restart if it was stalled.