PETA doesn't have a position on immigration; we focus solely on promoting animal rights. However, people on both sides of the immigration debate can support PETA's pro-vegetarian ad because the revenue would help reduce the cost of the fence for taxpayers and promote healthier eating, resulting in lower health care costs.
PETA's "focus solely on promoting animal rights" is not about promoting veganism. As a movement, veganism necessitates honoring the efforts of all anti-oppression movements who are striving to achieve the liberation of human and nonhuman animals alike. Regardless, Rajt betrays PETA's own proclaimed neutrality by evoking Right-wing arguments regarding taxes and health care costs. Nothing in the ad, or PETA's defense of the ad, makes any point for the rights of nonhuman animals. And while in a very narrow sense the ad is "pro-vegetarian," it is also very much anti-vegan.
No anti-oppression activist or organization would support PETA's scheme to subsidize/privatize the oppression of non-citizens. The ad clearly makes light of the violence non-citizens, and even citizens who are people of color, experience via the Border Patrol and anti-immigration policies. And while there are legitimate cases that can be made about health care, this would require carefully addressing the effects of inequality and oppression on health. As it is, the PETA ad does little more than reinforce anti-immigration propaganda blaming im/migrants for rising taxes and health care costs, which usually leads to an attack on public health programs in general and calls for increased privatization.
PETA has routinely aligned itself with the Right, having worked with McDonald's executives, Operation Rescue, the US military, and now the Department of Homeland Security, Border Patrol, and U.S. Customs and Border Protection. But when it comes to working for anti-oppression and with fast-food workers, reproductive health organizations, the people of Afghanistan and Iraq, or Mexican im/migrants PETA's "focus is solely on promoting animal rights." (And if we're honest, PETA doesn't even really support rights for nonhuman animals.)

