I can count on less than one hand the number of times I've ever used the word "speciesist" as a pejorative for someone who believes in human supremacy. I mean, let's face it, it just doesn't have the same pizzazz as "racist" or "sexist." Maybe it has too many syllables (though that doesn't seem to hurt "homophobia"); maybe an alternate name would be better. Taxonist? Cladist? Human Supremacist?
But there's a problem with "speciesist" aside from its clumsiness: it's counter-intuitive. It implies an equality of species that most humans are simply incapable of accepting. And that's an obstacle that repeated use of the word may not be able to overcome.
I've never much used the word for this very reason. Most people already agree that killing and hurting animals unjustly is wrong. Most people already have a sufficient-enough level of cross-species empathy that they can intuit why factory farming is wrong. There really isn't much need, in my view, to invent a whole new ethical system to promote veganism. We really just have to get more humans to take their own professed values seriously, and to think before they eat.
Every species is different from all others in fundamental ways. That is what it means to be a species. And while it's true that this fact alone is not enough to justify the horrid things we do to nonhuman animals, it's also not an ideological construct in the same way that, say, race or gender are. Humans and nonhumans really are fundamentally different, and the farther afield one gets from our clade, the more pronounced those differences get. Pretending these differences don't exist, or that they are irrelevant in ethics, is to my mind a losing battle.
I've always thought of the issue in these terms: animals have interests of their own, independent of how our species feels about them. And animals should be left alone to pursue those interests; the benefit of the doubt should go to them in situations where our own species or individual interest is not in conflict with theirs. When our interests are in conflict, those of animals ought not be dismissed simply because they are nonhuman.
In practical terms, this is a more than sufficient case for veganism: for most people living today, exploiting animals for food is completely unnecessary. That they taste good and are made convenient to us are not just cause for overriding animals' interests in themselves, and certainly not for the hell we inflict on them with modern farming practices.
While we're on the subject, I've only rarely ever used the phrase "animal rights," too, and for much the same reason I've avoided "speciesist." My view has always been one of a more laissez-faire approach to animals than a social contract: just let them alone, and leave them free to pursue their own lives and interests.
Does this make me an animal libertarian?