It’s embarrassing to the US that they’ve spent a good 20 some odd years, fiddling with the Middle-East for a various assortment of reasons. Only to lose Afghanistan in less than a week. All of that money. All of the lives involved. Wasted. Just so a group of tyrants with pre-school level of intelligence, maybe even less, take it over and ruin the lives of everyone not them.
Maybe that’s why the US has forgotten it, they don’t want the humiliating memory.