I've seen this in the media already a couple of times. If you say 'Anybody But Bush' (ABB), they think you mean just 'anybody' the wind blows in -- as if the town drunk or village idiot had a shot at the Democratic nomination. This is a convenient interpretation for the media since it gets them off actually having to explore what the eventual nominee has to say or his appeal to voters -- he didn't win after all on the merits of his ideas.
Of course, the context to 'Anybody But Bush' is anybody among the leading contenders in the Democratic party running to replace Bush. Among them, they're similar enough in policies, to be perfectly acceptable to most people. Those major candidates -- 'any' of them -- are what people usually mean when they say 'anybody but Bush'. Collectively, they were a pretty good bunch.