There isn't much in a mammal that will make a fellow sick should he eat it. There's a few bits one should avoid, but they don't add up to much. Most of the entrails are perfectly edible. Of course, one has to empty the gastrointestinal tract of its contents before chowing down, but the actual animal tissues are fine. Same goes for the bladder. Basically, just the skin and bones are tough eating, but not harmful. Bones can be crushed to expose the marrow and cooked, but I'd have to be pretty hungry to actually consume the bone itself. The skin is a pretty sizeable proportion of an animal and perfectly edible. Pig and chicken skin is consumed in western society, but not cow or sheep skin for some reason.
I'm not sure I would argue that animals were "made" to be eaten, but the fact is that a lot more of an animal can be eaten than western culture chooses.