Because everyone starts out somewhere. When I first came to Hive, I started out doing CnP stuff as well, and I had people guide me. Also, I realized he may not know all the terms people have been throwing at him (this might just be wishful thinking though). And while he may never do any effort to improve, perhaps explaining to him that there are people who have to take time out of their schedules to clean up after him might at least convince him to stop it with this constant uploading of cra... ehh... human excrement.
But I guess the real reason I do it, is because no one else does. Lately we've had so many shitty recolors uploaded on the skin section, and everyone else (perhaps save Apheraz) seem to have either given up trying to explain what's wrong with these skins, or just don't understand Hive's rules and standards ("Nice 5/5" -> I swear, I could strangle these people...)