She doesn't straightforwardly endorse global vegetarianism, let alone veganism; she mainly outlines an approach for evaluating objectives, then passes the buck when it comes to more specifically how to achieve those objectives. Her approach on vegetarianism seems to be a "needs more research before we can say whether it's a good idea."
One must bear in mind, though, that she's talking about justice and basic entitlements. Many people who personally think that being a vegan is the right choice (when it is possible) would hesitate to call upon the state to legally enforce veganism. (Those with low nark levels, one might say)
She seems to regard vegetarianism as a somewhat tricky issue, but seems to be more concerned with research.
Our world contains persistent and often tragic conflicts between the well-being of human beings and the well-being of animals. Some bad treatment of animals can be eliminated without serious losses in human well-being: Such is the case with the use of animals for fur, and the brutal and confining treatment of animals used for food. The use of animals for food in general is a much more diffiuclt case, since nobdy really knows what the impact on the world environment would be of a total switch to vegetarian sources of protein, or the extent to which such a diet could be made compatible with the health of all the world's children. A still more difficult problem is the use of animals in research.
A lot can be done to improve the lives of research animals without stopping useful research. As Steven Wise has shown, primates used in research often live in squalid, lonely conditions while they are used as medical subjects. This of course is totally unnecessary and morally unacceptable and could be ended without ending the research. Some research that is done is unnecessary and can be terminated, for example, the testing of cosmetics on rabbits, which seems to have been bypassed without loss of quality by some cosmetic firms. But much important research with major consequences for the life and health of human beings and other animals will inflict disease, pain, and death on at least some animals, even under the best conditions.
I do not favor stopping all such research. What I do favor is (a) asking whether the resarch is really necessary for a major human capability; (b) focusing on the use of less-complex sentient animals where possible, on the grounds that they suffer fewer and lesser harms from such research; (c) improving the conditions of research animals, including paliative terminal care when they have contracted a terminal illness, and supportive interactions with both humans and other animals; (d) removing the psychological brutality that is inherent in so much treatment of animals for research; (e) choosing topics cautiously and seriously, so that no animal is harmed for a frivolous reason; and (f) a constant effort to deveop experiment methods (for example, computer simulations) that do not have these bad consequences.
Above all, it means constant public discussion of these issues, together with an acknowledgement that such uses of animals in research are tragic, violating basic entitlements. Such public acknowledgments are far from useless. They state what is morally true, and thus acknowledge the dignity of animals and our own culpability toward them. They reaffirm dispositions to behave well toward them where no such urgent exigencies intervene. Finally, they prompt us to seek a world in which the pertinent research could in facto be done in other ways.
Nussbaum, Martha and Sunstein, Cass, ed. Animal Rights: Current Debates and New Directions.
Oxford University Press, Oxford, 2004, page 318.
As you can see, she has quite a ways to go before she's narky. I still think she has some interesting things to say, though, regarding her arguments against Rawls, Singer, etc.
I'm somewhat skeptical about the capabilities approach myself -- is it really all that great if I get to "exercise my capability" of feeling grief? I can see a case for it, but I'm skeptical nonetheless.