David Salisbury has a nice article on animal sacrifice at http://www.daviddsalisbury.com/#!Sacrifice/c22a6. It's not a priority topic for me since I don't know anyone who practices animal sacrifice, but it makes its points well.
Some of these points can be applied to other issues as well, including the issue of Morris dancers wearing black face paint. Just because people did it in the past doesn't make it cool.
It also applies to arguments about any kind of animal cruelty -- yes, unless you are completely vegan, you are still hurting animals, but if you save the life of one animal, that's something.