"Let me get this straight. It's perfectly fair for Barack Obama and his cohorts to repeatedly disparage President Bush's foreign policy as 'cowboy diplomacy' but unspeakably horrific for Bush to analogize the Democrats' approach to foreign policy to appeasing Hitler?"

Not "unspeakably horrific." But otherwise, yes, you've got the basic idea. The basic idea is that calling somebody a cowboy isn't as bad as calling somebody a Hitler-appeaser.