What Hitler was demanding at Munich was not unreasonable as a national claim (though he was making it in a last-minute, unreasonable way.) Germany's claim was that the areas of Europe that spoke German and thought of themselves as German be under German authority. In September 1938 the principal remaining area was the Sudetenland.
So the British and French let him have it.
In a way, I'm okay with this. If the Seattle Times wants to join George Bush and me in equating Barack Obama with Neville Chamberlain, I welcome them to the club.