There is sadly a small segment of animal-rights or environmental advocates who let their cause mutate into a sort of misanthropy or disregard for humans. At its mildest levels it manifests as the half-joking comments of "we don't deserve dogs" or "dogs are the best people" that are all the rage on imgur et al., at its more severe levels it becomes anger or violence against those perceived to be enabling oppression of animals seen as pure innocents.