Seriously guys its a theory the whole omnivorous ceratopsid thing. I don't consider them omnivores any more than i consider a hippo or a deer an omnivore. Sure the extant animals have been known on some rare accounts to eat meat but but looking at their morphology and digestive tracts, they are primarily plant eaters. Heck, my dog eats orange slices and pretty much anything else I have on my plate if offered...but meat is still his main diet. I guess my point is that animals will occasionally supplement some weird stuff into their diets but its not like its a very common occurance. I wouldn't be surprised if we went back in time and actually saw the mesazoic, ceratopsids wouldn't be the only plant eaters occasionally grabbing some meat here and there. Its one of those ideas thats really different and pertains to a well known type of dinosuar...therefore it gets a LOT of attention and eventually people start accepting it as fact when in reality its still just an idea that may or may not be true.
We don't have a digestive tract of a ceratopsid yet but their morphology still suggests a plant eater as does their known numbers in their known ecosystems.