If those are your criteria, then I wholeheartedly suggest Ted Nugent.
He is constantly active in bringing about change for our hunting rights. He believes in hands on conservation. He runs a non-profit organization for kids. He is always giving of himself to help other either learn about hunting or becoming a better hunter. Most people find him harsh. That's only because he's not politically correct...boo hoo. lol He tells it like it is and doesn't sugar coat it.