Some of the things you mentioned here are some of the exact reasons why I stopped practicing Wicca and totally left the religion behind 4 years ago. The ethics are (to me) completely illogical and impossible to follow, much like Biblical ethics. There are too many interpretations that can be made for the system to have meaning. Obviously, if you're a British Traditional Wiccan, this probably is not a problem for you, but I've never met two American Wiccans, of whatever tradition or solitary, that agree on what the Rede means and how it should be applied to daily life. It can cause a lot of disharmony, both in the greater community, and within yourself.
About animal sacrifice, anyone who is seriously practicing it does so
because of the respect they hold for that animal. That's why any occasion warranting such an event comes with a huge feast. Commemorating the seriousness of that event, thanking the animal, consuming the animal. If anything, it's more respectful that an animal is killed and eaten in this way than killed to "just serve the purpose" of everyday eating, as =
EternalxRequiem said below.
But I do want to clarify about my own views -- I am very passionate about animal welfare, I'm in veterinary school right now, and I've been raised respecting animals my entire life. I don't think it's wrong to eat meat, but I cannot understand how someone could have a problem with an animal being killed for sacrifice, then eaten, but not have a problem with factory farming. You're right, Northwind, sacrifice has become a dirty word, and that's a terrible trend. It used to be such a sacred act of community, nourishment, and respect for the animal and ultimately the Gods. Now it's something that is treated shamefully. It makes me very sad.
(But just to note, animal sacrifice isn't illegal -- one only needs to get the correct slaughter permit. As long as you have a slaughter permit, it doesn't matter legally what your reason for slaughter is. This is why Greek Orthodox Christians can slaughter their own lamb for Easter, why Vodou practitioners can slaughter roosters, etc. As far as I know, this is the case in each state, just with differences in how to get the permit, things like that.)