maybe if they would stop cramming down the propaganda that I'm some mass murderer or horrible terrible person for eating eggs, meat, drinking milk, and enjoying some chicken (amongst a plethora of other things), people wouldn't have such an issue with them.
Either way, as I said, I'm not entirely sure which amino acid it was (or if it was even an amino acid) that is not found in vegan diets, so I'd have to find out from my friend, again.
I'll post back here, when I do.
I'm quite the Libertarian (though there's a few issues I'm a little iffy on...but hey, not all Libertarians are the same). I detest animal cruelty, but I also recognize the danger of assigning rights to animals--there's been several cases where people have lost their homes because of an endangered species--and it's no wonder they take to the "Shoot, shovel, and shutup" ideology--if that law wasn't there, people probably wouldn't do that, as there would be no repercussions for having it on your property.
I'm not sure where Libertarians get the idea that animals have rights...it goes against the majority of Libertarian thinking, not to mention it's mostly a collectivist ideology.
First, some vegans, just like some libertarians, seem pretty much like jerks to other people. That doesn't mean that it is okay to spout misinformation about them. Now, I don't think you were being malicious. What I am saying is that what you were giving out about the missing amino acid(s) is misinformation. Both the NIH and American Dietetic Association recognize that vegans can get all required nutrients without eating meat. So, it doesn't matter what your friend says. It is true that some amino acids are not found in plants, but all such amino acids can be produced in our body. There are 8 essential amino acids (of 20). All can be obtained from an entirely non-animal based diet.
As for your concern about animals having rights and Libertarianism: I don't know why granting rights to others is collectivist. I am not saying animals have a collective right, or that species have rights. I believe that individuals have rights. What you are concerned with seems to be the environmentalist bent on protecting biodiversity, which isn't based on the assumption that animals have rights.
I don't assert that animals have property rights (except to bodily integrity), but only because they can't really be said to acquire property. They may have no right to land, or anything like that. What they have a right to might be something like a right to life, that is not a collectivist idea. It is simply to extend a right we recognize in humans to that of animals.
In any case, we don't need to say that animals have rights. What we need to do is recognize that they are ethically important. We should recognize that their ability to feel pain is ethically important, not because they are property, but because the pain matters to the animal. That doesn't mean we need to grant them any legal rights. Rather, it means we need to recognize that we cannot simply treat them as we wish.