Take another example. "I'm fine with such and such a religious group, I just wish they would stop trying to convert me." Once again, this ignores the fact that, because of the very nature of someone's beliefs, for them to not try to convert you would be to neglect their moral duty. After all, they believe that if you are not converted you will suffer, which means, in fact, that not attempting to convert you would not only be neglecting their moral duty but, specifically, neglecting their moral duty towards you. To not try to convert you would be akin to letting you drown when they had an opportunity to try to rescue you. Similarly, it is absurd to expect the religious to keep their faith separate from their politics: if one believes, for example, that homosexuality is a sin and dangerous to our nation's spiritual well-being, it would be negligent for them to not try to combat it.
Now, one can argue whether the killing of animals for meat does constitute murder*, or whether such and such is the path to salvation, or whether homosexuality is a sin. But this is exactly the issue that is at stake: whether or not someone's beliefs themselves are sound.
*incidentally, I myself am conflicted on this point and, as such, have not become a vegetarian.