First point: if someone agrees to reduce their consumption of meat, I would definitely commend that. I've even done that on DU, even though the idea of congratulating someone who continues to eat eggs & dairy is completely inconsistent with animal rights. The problem is when large orgs like PETA promote "vegetarian" starter kits, or when their list of "accidentally vegan" contains products that are not actually vegan. When encouraging someone to reduce their consumption of meat, the emphasis needs to be on the eventual goal veganism, not in advocating for vegetarianism. As I said, the consumption of any animal products is not and cannot be in any way consistent with a theory of animal rights anymore than civil unions can be consistent with a theory of GLBT rights and legal segregation consistent with a theory of AA rights. You don't have to be an asshole about it, but you can make it clear that you cannot meaningfully advocate for animal rights while continuing to consume and use byproducts of the meat industry like eggs and dairy.
Second point: it's not just about marketing a veggie burger, it's about PETA congratulating Burger King for resorting to controlled-atmosphere killing, or Temple Grandin for designing slaughterhouses. I'd even argue that giving an award to Pat Buchanan, a racist holocaust denier, or HSUS endorsing Rick Santorum because of his stand on puppy mills, is inconsistent with the larger goal of tying animal rights to progressive causes. While CAK may be a nicer way to slaughter an animal and deny them their basic rights, it's not consistent with a theory of animal rights. Burger King, Pat Buchanan, and Temple Grandin are the enemy, plain and simple.
Then there's this letter:
http://www.satyamag.com/sept06/edit.html. This is disgusting. Animal "rights" groups should never be promoting the consumption of meat, much less giving their implied endorsement with the label of "compassionate." Meat, eggs, dairy, leather, fur, etc. are never compassionate. They are all predicated on denying the basic rights of animals to live free of human intervention.
Third point: PETA's use of nudity and shocking images of people of color has distracted the public from their views on animal liberation and turned it into a discussion about "comparing people of color to animals." Instead of reacting sensitively to these completely legitimate concerns (the context of comparing african-americans and women to "animals" has a nasty history in this country that one would have to be completely historically illiterate not to notice), they pretty much ignore them. It's completely tone-deaf, and strikes me as part of the problem with white male privileged liberals as a whole. This struggle doesn't belong to you: it belongs to the oppressed peoples or animals that you are supposed to be fighting for. And if your message is insensitive or offensive to these peoples, you've failed. Telling african americans or women that their concerns are not of value is as paternalistic as the institutions that you are supposed to be fighting against.
I'd also add that some members of DU are not nearly as progressive as they think they are, so their reactions to sexist or racially-charged imagery is hardly the standard I'd use.
Fourth point: within a consistent abolitionist theory of animal rights, I would argue that cruelty is irrelevant. Slavery wasn't wrong because slaves were sometimes treated badly, it was wrong because the entire institution was a violation of the basic rights of human beings. Domestic abuse isn't wrong because women are treated badly in abusive situations, it's wrong because it violates the basic rights of women to live free of fear and coercion. Factory farming isn't wrong because it's cruel and torturous to animals, it's wrong because it violates an animal's right to have his or her interests considered.