Gaaah! Would someone please tell

Gaaah! Would someone please tell me why eating rat heads is gross but chewing cow ass is not? Now don't get me wrong, I'm not saying there's anything intrinsically wrong or gross about munching on some yummy cow ass. I just fail to see what's so disgusting about crunching rat heads. If you think rat heads are dirty or prone to spread disease then I think you're fooling yourself about the cleanliness of the meat you eat. If you cook your meat well, you're probably not going to get any diseases; well, except for vCJD, cancer, and heart disease.