Canadians view it as a rebellious thing. I'm having to draw upon memory but it can symbolize something simple like pride in rural lifestyles. As far as that whale-war dude is concerned, I have no idea. I just found it funny after watching some YouTube clips of his.
obviously the last thing I would expect is some vegan, anti-whaling left-of-center politically-motivated person to have stickers like that. But here we are and I certainly live in clownworld.