I don't think this is a surprise to anyone who has been paying attention. Stewart and Colbert are generally humor that you need to be more informed to understand. Fox News has a lot of bright, flashing lights. Stewart and Colbert challenge their viewers. Fox News tells their viewers what they want to hear.
If you want to enjoy Stewart and Colbert fully, read a book. If you want to enjoy Fox News completely, hit yourself in the head with a rock.