There are several important ideological differences between animal rights/liberation advocates (ARLs) and the rest of us. These are important to consider as we must understand those who are attacking our way of life. The more we understand, the better able to fight back we become.
The following information is taken from a bioethics article on animal rights activists and violence at The Discovery Institute.
We have to understand that ARLists do not share a common frame of moral reference with the rest of society. Whereas most of us believe that humans have the highest moral value, it is an article of faith among ARLists that no moral distinction exists between humans and animals; "a rat, is a dog, is a boy," in one animal liberationist's infamous assertion. Thus, while most of us believe that we have a positive moral duty to treat animals humanely and support punishing people that abuse them, ARL movement devotees believe — not metaphorically, but literally — that we have no right to use animals for any purpose, not even as seeing-eye dogs.
In this surreal moral prism, real evil is reduced to banality as advocates equate cattle ranching with human slavery, Mengele's notorious twin experiments with testing the safety of stem cells in rats, and the sending of Jews to the gas showers at Auschwitz with eating a steak. Lest you think I exaggerate, in its pro-vegetarian "Holocaust on Your Plate Campaign," People for the Ethical Treatment of Animals (PETA) asserted, "The leather sofa and handbag are the moral equivalent of the lampshades made from the skins of people killed in the death camps." What's worse: They meant every word.
ARList ideology is a frontal attack on human exceptionalism. In this sense, it is profoundly anti-human, both in its first principles and in consequential effects. This is undeniably subversive to the moral order. Believing that humans are unique and special is essential to promoting the ideal of universal human rights. After all, if we are just another species of animal in the forest, that is precisely how we will act.