One of my pet criticisms as well. Where there is a key location that is unmistakable (Los Angeles, Albuquerque, Tucson), no problem; but when it's Oakdale, Decatur, Springfield, or Centerville), it does behoove the poster to do the parenthetical, two-letter state thing.
Don’t you love Springfield, there’s probably 57 of those in these Obami states!