After the US was attacked on 9/11, some accused Saudi Arabia of having a part in the attack. The CIA website, cia.gov had a page with the names and nationalities of the 19 hijackers. That page has since been moved to 911myths as well it should. The page lists 15 of the hijackers as Saudis, but that was before the attack was properly investigated. The first version, before it was properly massaged into the proper shape, was that 19 Arabs, 15 of them Saudis, met in the Arabian Peninsula, decided to destroy the World Trade Center, flew to Berlin, then London, then the US where four of them took jet passenger airliner flying training in Florida, then, on 9/11/2001 (in US date notation) they hijacked four aeroplanes. The hijacking relied on the hijacking protocol from before 9/11: do whatever the hijackers demand, get the planes safely on the ground, and then let the police deal with the hijackers. So it proved easy to hijack the four planes, and the hijackers then used two of them to destroy the World Trade Center, one to damage the Pentagon, and one crashed when the passengers tried to take control of the plane from the hijackers. Just because we have the records from the flight passenger lists, from their passports, from the flight training schools in Florida is irrelevant, of course, that is not how the US investigates major crimes, it uses much more sophisticated methods.
Ignoring such useless distractions as facts, proof, and evidence, Bush, Jr immediately announced that the attack was planned in Afghanistan, and the main hijackers were members of the Taliban, so the US troops went into Afghanistan in October, 2001. The main perpetrator of 9/11 was said to be Osama bin Laden, who was a) a senior member of the Taliban or b) someone protected by the Taliban or c) someone whose main base was in Afghanistan and who was closely allied with the Taliban or d) maybe something else. What, exactly, was, of course, irrelevant. Afghanistan was responsible for 9/11. Of course, Osama was never found in Afghanistan, but no matter. Osama did say that the US World Trade Center housed many murderers who must be killed. How, exactly, they must be killed he did not say, but bombs were planted in the World Trade Center in 1993, killing six people and injuring thousands, and the plotting to destroy the World Trade Center continued until it was destroyed, and it was all Osama's doing. Of course, many Imams in Saudi gave their Friday khutbahs saying that the World Trade Center must be destroyed, but that does not change the fact that Afghanistan was responsible. Those khutbahs were based on facts that would not be revealed to the world until after 9/11/2001, when the motivation for 9/11 appeared in the book Confessions of an Economic Hit Man by John Perkins, published in 2004. He explained how he convinced Indonesia to accept a predatory loan for a construction project that was supposed to pay for itself, with returns more than enough to service the loan. Only the project returned nothing, and the loan was unforgivable sovereign debt, so Indonesia had to repay. Subsistence farmland was converted into cash crops, and the former farmers starved to death. Mines were dug and the waste dumped in the drinking water and many more died from having no potable water. So the Imams and Osama all said the people in the World Trade Center had murdered more than 1 billion Muslims and must be killed. As Perkins made clear, there is no evidence that any of the people who arranged for the economic hit men to go making those predatory loans worked in the World Trade Center, but Osama and the Imams were still convinced.
The total number killed by predatory loans is in the millions, not a billion, and included only a small percentage of Muslims. John Perkins and the other Economic Hit Men foisted those predatory loans off on Latin America, Asia, and Africa, so most of those who died were not Muslim but Christians, Buddhists, & etc., but still, those Saudi Imams and Osama blamed the World Trade Center for murdering Muslims, they knew what those economic hit men had been doing.
So obviously, Osama was entirely to blame (well, plus the many who followed him, but he was still the main one, those Saudi Imams who said the same things have been found blameless by the US courts, the best legal system in the entire world).
Obama asked actors to pose as physicians and say they were giving free vaccines to get Pakistanis to let them investigate homes in Pakistan looking for (and finding) Osama. Since then, many Pakistanis are very reluctant to take vaccines, but this trifle does not detract from Obama's managing to kill the person who was entirely responsible, with hundreds or maybe thousands of others, for the 9/11 attack on the US. Nor does it reduce Afghanistan's guilt. They were entirely responsible for 9/11 (with many other countries) and had to be punished, and punished severely.
Most commentators agree that Afghanistan remains a big problem. They were entirely responsible for 9/11, and, as soon as the US pulls out, they're sure to do it again. But Biden says the US has been in Afghanistan too long, even though it was the presence of the US in Afghanistan that prevented the terrorists from committing another 9/11.
The fact that none of the 19 named as hijackers had ever been anywhere near Afghanistan, as proven by their passports that were scanned in full and recorded when they entered the US does not reduce Afghanistan's guilt. Osama was there. Briefly, but he was there. So it is clearly necessary for US troops to remain to keep America safe, and Biden is letting the US guard down by withdrawing.
Biden has promised that the troops will not foolishly return to the US, they'll be relocated to other bases in the area, and their intelligence will direct the daily drone strikes on Afghanistan run from the US. Those strikes will kill the many, many terrorists still there, terrorists who include many infants and great-grandmothers.
So the US will sort-of, kind-of be 'out of Afghanistan' but at least the drone strikes will continue, and surveillance of Afghanistan will continue from bases near Afghanistan.
But still, all the experts say that Afghanistan does nothing but plot attacks on the US like 9/11, and only the presence of US troops ever since 9/11 has prevented a repeat, so, even with the daily drone strikes and constant intense surveillance, Afghanistan is sure to do another 9/11 if US troops do not remain to prevent it.