humans are animals, also. i have always been a vegetarian if seafood, vegetables and fruits qualify
This is primarily why some tribes of different cultures allow consumption of humans. e.g. long pigs, because they taste similar to other animals e.g., (which I do not condone of the slightest), but what they do consider morally ethical in their culture has a lot to do with their core beliefs, (which would be seen as barbaric or grotesque because of the sheer nature of it), compared to our western culture, and would be opposed to idea of veganism based off the very concept of what it stands for, as well as vegetarian diets for that matter.
Since I do condone in eating seafood/sea animals though, and not so much animal meat, I regard it as a step up from veganism, (as eating vegetables and fruits alone I'd find difficult to stick with), and apart from that, has many health benefits, such as Omega 3's from fish, seaweed etc.
That does not mean to say though, I am against any kind of religion or any of their food practices, out of respect, as every culture (including ethnicity) and the food they eat, that practices religion of any kind, take this into consideration to some degree, and what may be seen as ethical to one culture, may not be seen in the same light as a different culture, and so on.