Heard on the news today that PETA also said a little Polar bear cub being raised by hand (it's mom rejected it) in Germany would be better off dead than being raised by humans. The news story called it a "right to life" issue, on behalf of the bear. The film clip of him was adorable - can't imagine that being dead is in any way, shape, or form, a better alternative.

As far as the bumper sticker, I would think that if the art is different, that would suffice. I don't think they can "copyright" just a statement like that.