Biden takes the blame, because he is in charge. Fact remains that over 18 months ago the US signed a peace deal in which they committed to withdrew forces by May of this year.
Biden extended this to end of August, but this decision to withdraw was flagged months in advance. Overconfidence in the stability and effectiveness of the Afghan Govt and military has led to the current chaos. And ‘overconfidence’ is putting it politely.
The French started evacuation in May and were widely criticised as it indicated a lack of confidence in the Afghan Govt.
The real blame is the failure by the US and allies after twenty years of occupation, only to end up with a Govt and military that lasted about twenty minutes.