I said it here at LGF just the other day- a main reason why Colbert over anyone the right wing likes comes down to right wing humor itself.

Right Wing Humor is just plain generally brain dead and dull. It makes for very boring TV.

It consists mainly of throwing childish insults at anyone opposed to the dogma or is of another race, culture, or ethnicity. Visual insults are best because they require very little thought and often make no sense- a photoshopped Pelosi head on a Miley Cyrus body will do nicely.

As I stated the other day, right wing humor is typified by the playground gag of one guy kneeling down behind the target, and other guy pushing the target over . Hurr Hurr.