Who did? Are you talking about the pickup trucks they left on the tarmac? I don't know the choices Biden had so I can't say how much of a screwup his withdrawal has been. It looked terrible at first, especially from a public relations standpoint, but they seem to have recovered some.
I'm sure you want it to be an unmitigated disaster, but the evacuation of people is far from that. I think the media rollout of the withdrawal was a disaster at first and they should've sold it better. OTOH, maybe Biden and the Pentagon chose to surprise people with a quick evacuation and not give naysayers the time to bitch and moan about it. It would be interesting to know how long the Pentagon and the Cabinet knew this was going to happen and if they were all in agreement beforehand.