KOUU 1290 in Pocatello, ID is AM stereo.
It might help to check your facts before making a grossly incorrect pronouncement. A web page with current AM stereo stations is available here
I had only considered the one I worked for, any of which would gladly sell you the stereo equipment they wasted money on. When I was working in Chicago we had two all-polka stations, so it shouldn't surprise me that there are still some AM stereo station in operation.
Kinda' like the "cave man" commercials for Geico.