The Simpsons are very adult oriented..they are on prime time on Sunday after football because that's the demographic they target and do very well in it. That being said even Looney Tunes aren't suitable for children by today's standards. I can't count how many times Daffy Duck has gotten his beak blown off by a shotgun or Elmer Fudd, Bugs, Tom and Jerry, Road Runner or any cartoon of that era has been shot or shot at someone. Even talk about that kind of stuff in school today and you are suspended and the bomb squad called.
Point is that it's all subjective to an extent. There are plenty of older shooters that don't contain gore but you still have the whole pointing a virtual gun at virtual people issue everyone likes to get all pissy about. There are also plenty of games that require the same use of spatial awareness and fine motor skills that are used in FPS that aren't shooters.