I’ll tell you why.  

Because back in the '70s, USAA was an insurance company for all officers in the military.  And as Vietnam was winding down, a lot of officers were in and coming out of the services.  It was run by real military officers, and provided all sorts of services worldwide.  There was a retirement community developed in San Antonio. Not sure what ever happened to that.  As time went on, USAA started taking NCO's, and then all enlisted, and all family members.  The thing just grew and grew, started farming out different insurance products to other 'partners'.  
Been with them for 50 yrs, and they are providing me with the lowest rates on all of my insurance, other than a motorcoach.  But it still pi..es me off the way the company has become.