Having torn into an anti-animal-rights article a few posts down, I should note that pro-animal-rights authors are hardly free from fuzzy thinking and unoriginal arguments. Such is the effort by Jan Deckers
(subscription req.) in the Journal of Agricultural and Environmental Ethics. Deckers' theme is to deny that vegans are "sentimental" by showing that there are good reasons to hold the vegan position. The reasons he surveys are well-known ones -- harm to human and environmental health, causing pain to animals, and the wrongness of killing animals. On the first point he cites the most up-to-date research in support, but adds nothing new philosophically. On the second, he plays with some nuance that he feels Peter Singer misses, but again there's no major new claims there. The abstract would have us believe that his challenge to Tom Regan's views on the third point is a major contribution of the article. Unfortunately, his challenge consists largely of a perfunctory citation of Whitehead to call into question Regan's assumption that plants lack awareness. I'd like to argue against this view, since what little Whiteheadian philosophy I've come across has always struck me as unfounded speculation and playing up the way its conclusions sound more radical than they really are. But Deckers barely explains what Whitehead says, much less why he says it. And in any event, the practical implications are dulled by Deckers' supposition that animals have a stronger dislike for death than plants and thus it's still reasonable to be more concerned about killing the former.
Another too-brief bit in Deckers' article is his exploration of why many people suppress their feelings of sympathy for animals. I think it would be interesting and useful to read a detailed ethnographic study of how children's feelings toward animals develop, and how they incorporate understandings of pets vs wild animals vs food animals vs pests and any cognitive dissonance between categories, and how this manifests differently in different places and cultures (perhaps such a study has been written and I just haven't run across it). Unfortunately, Deckers' exploration consists mostly of briefly recalling how he and another author were urged, against their inclinations, to kill animals to prove they were real men. This exploration is overhung by a not-quite-stated presumption that children naturally see the wrongness of killing animals but are twisted by the patriarchy etc. This approach seems to be to be both based on a psychologically/anthropologically false romanticism, as well as highly ineffective at swaying anyone who doesn't already think non-vegans are morally corrupt.