I'd guess occupation is probably more about trying to prevent it from becoming a full-on narco state (estimated the Taliban pulls in $400+ million a year in opium trade), haven for terrorists, influencing the balance of power in the region, etc.
obviously, yes
By any measure the occupation has been a resounding failure, if success means achieving any of those goals, which should surprise exactly no one who had ever read like, literally any book about the history of Afghanistan.
there are many, many other places around the world where "women + children are at the mercy of fundamentalist forces" (for example, yunno, Saudi Arabia) or etc, that the U.S. - and every other power - are content to let be. I'm sure some ppl who employ that line are sincere - and many are not, or less so - but in practice it's just one of the 21c versions of using the threat of Communism to justify decades of coups + other CIA etc fuckery