I can't really explain it, but I know (History Channel) that OBL was persona non gratis in Afghanistan when he fled there from Sudan.  I can't remember why they let him have his training camps there.  Also, al Qaeda is no longer the same tiny centralized al Qaeda that attacked us on 9/11.  It's now a bunch of many little al Qaedas, home grown, home spun and everywhere.  OBL is now pretty much just the inspiration for them.  That's why eradicating al Qaeda is now so much more complicated.  Plus OBL is a Sunni, so that may factor in with whatever religious divisions are going on.  We tend to think "Muslims" are this single entity when in fact they're as diverse as "Christians" or "Jews".   Also, OBL wants a religious caliphate, where other Sunnis want to keep their national as well as religious identities so that might factor in too, who knows?  This whole thing is mind boggling in its complexity yet we treat it as a nice simple evil/goodness thing with "Muslims" evil and "Christians/Jews" good. 

 

Did you try the State Department web site?