It's just a TV show. Entertaining and bringing back viewers is goal #1,2,3. I personally don't have a problem with Cody's personality (and I liked his When All Hell Breaks Loose book), but many/most TV shows with more than one cast member need an unlikable character. People like to dislike people on TV or like to see some friction on-screen. Actually, I'm sure there are plenty of people who dislike Dave and like Cody. At times, I get annoyed by Dave's disparaging attitude toward Cody.

Cody is an expert on aboriginal culture and primitive living. It's not surprising that his approach seems "extreme" but that's probably because his paradigm of "normal" out in the bush is not the same as ours. It may not come out in the show, but to me, Cody is more about living in the bush while Dave is more about surviving the bush and getting back to civilization.