Not sure about the 70's support, news to me, but we definitely and cynically supported many branches of Mujahadeen to wage guerilla war against the Soviets in the 80's. The Mujahadeen were NOT a single organization, not all from the same ethnic groups, and in some cases were enemies in all other contexts than the struggle to drive Russia out of their country.

When Russia beat a retreat we then cynically dropped Afghanistan from our radar screen and it predictably blew up in a vicious civil war. Some of the conflict was between Hazara (Shia) and Pashtun (Sunni) Mujahadeen, an old and seminal conflict in Afghanistan and across the Muslim nations. So yes, we used the people of Afghanistan as canon fodder in our stupid "cold war" with the USSR, and then dropped them and left their many warlords and ethnic groups to fight it out for position and control among themselves. Our debt is enormous, possibly could have been paid to some extent in the years after 2002, except that our idiot president (W) lost interest and attacked Iraq.