patrick.net

Thought it was at least partially the CIA's profitable heroin trade involvement, with the late HW Bush and Clinton in cahoots, the modern day equivalent of a covert 'opium wars'.
The Taliban was shutting down the opium fields, and CIA could have none of that.

This article is from 2009.
https://www.hudson.org/research/6496-does-the-u-s-still-have-a-vital-interest-in-afghanistan-

No vital interests are related.

Nor in this article from 2016. No reasons, just the NGOs bitching about a humanitarian crisis and a US Military officer complaining that NGOs can't distance themselves from security forces and then complain when they're hit by mistake or not protected from attack. The article includes the words "Vital Interests" , no actual reasons other than the BS 9/11 excuse (see below) are in this article.
https://www.brookings.edu/blog/brookings-now/2016/01/08/afghanistan-in-2016-still-vital-interests-still-reasons-for-hope/

17 years and elections are still frought with violence, 78 dead and 1/3rd the polling stations never opened. Again, article gives no reasons.
https://www.brookings.edu/blog/order-from-chaos/2018/10/23/ballots-and-bullets-in-afghanistan/

Whenever the Elite and their Scholars for Dollars have nothing to offer as a reason but a country that had no terrorists participating in 9/11 and Human Suffering, I know they're full of shit, because people are suffering in Honduras, Belize, New Guinea, Somalia, South Sudan, etc. just as bad if not worse from rampant violence and nobody deploys troops there.

The only thing they bring up is 9/11, but Afghanistan is just where OBL was allegedly (if he wasn't really in Pakistan) at the time, before that he was in the Gulf and/or Sudan. The hijackers and the financing all came from Saudi Arabia, Egypt, and Morocco Muslim Brotherhood organizations. So the lesson is to kill more Khashoggis and other Muslim Brotherhood Shills, and for starters get everyone to declare it a terrorist group. Oh, and have a Muslim Ban at home, with exceptions having to prove they are not Muslim Brotherhood members by going to multiple interviews and spending a few thousand on a visa, maybe putting down a $100k bond to study, work, or visit the USA. This would survive the Supremes if it was characterized as an political ideology (which it is, for a theocratic state) and by countries rather than by "Islam".

But that's another issue.

Why are we there?

The human rights BS is of course merely window dressing for the MSM, as usual.

You might want to read about the "magic pipeline." Texas Governor George W Bush met with the Taliban in Texas to try to encourage them to sign a pipeline deal. They refused, so President George W Bush toppled them and replaced them with a former Unocal/Chevron executive named Hamid Karzai, who signed the pipeline deal. When the W administration (illegally) diverted resources from Afghanistan to Iraq, the Afghan war failed, and the pipeline could not be built. Unocal/Chevron has not given up on that pipe dream (an article on Yale.edu claims it isn't a pipe dream), and the MIC wants always more procurement, so we are still fighting there. W was probably America's worst President, and started a war that has now taken on an impossible mission (prop up a Muslim democracy) where we can never win.

Also, many people do not really understand Islam, so they try to prop up Muslim "democracies" and make deals with Muslims including the Taliban. It's an old habit that has metastasized since Nixon's disastrous deals with KSA gave Muslims the power to corrupt western governments and media. The first thing to understand about Islam is that it is a word that means submission; it spreads by the sword, and its only universal language is one side submitting to another.

If we want a pipeline, there is only one way to do it. As Donald Trump said, "We take the oil." (The pipeline would mainly be for gas from Turkmenistan, but the same rule applies.) We take whatever it is, say our companies are building whatever they want, and anyone who goes within a mile of it will be shot on sight. Ditto any "Muslim" government that we dislike, because Islam hates us and that gives us license to hate them right back. "Do unto others as they would do unto you, and do it first." They would kill us if they could, so if they live to see the dawn then it is because we allow it, and they will let us build our pipeline to sell our gas if they want to live. They might use long range weapons to damage the pipeline, but we have more long range weapons than they have. That is the language of Islam; if they had the guns and we had the oil and gas, then they would take whatever they want and kill anyone who objects.