Go Flip, go Flip, champion of the feline!
First off, I have never, ever, ever ever seen a cat roll around in it's own shit, your shit, anything's shit for that matter.
Second, dog saliva is actually pretty clean if I recall correctly. Maybe not technically "clean" but actually very few harmful bacteria. Despite all the kaka-munching.
Cats and dogs both have their respective qualities and let downs. In the end it's whatever you prefer. But to say stupid untrue shit about one animal just cos you don't like it, that makes you a person worthy to get shot.
Dogs are great. Cats are great. Period. End of story.