A good question:
How can someone being portrayed as "the biggest celebrity in the world" also be painted as radical and out of the mainstream? Either Obama is like Britney Spears and Paris Hilton: a fluffy, substanceless, mass-consumed but empty celebrity-for-celebrity’s sake, or he is an unfamiliar and dangerous other with a hidden anti-American agenda.
When these kinds of attacks contradict each other, it's a good bet that both are being made not because the McCain camp actually thinks they're true, but because they're just trying to find anything to bring the guy down. You throw it all until something sticks. Just like the Clintons did. And that worked out great for the Clintons, didn't it?