A teacher at my school received a ham as gift from one of her students (I think it was a roast or something big). Not wanting to offend the student and tell her that she wouldn't/couldn't eat it because it was portk, she took the ham and then regifted to her downstairs neighbor who is not a believer. Her reasons were that of course she didn't want to offend her student who had thought of her (and working within this culture I understand how the student wouldn't see the reason but the rejection) but also it was food and she didn't want to throw it away either. That is why she gave it to her neighbor. I know as Adventists that we would never serve pork to anyone but would you have given the the roast to a non-believer or would you have thrown it away?
Sure vegetarianism is good. We can recommend it, but we can't enforce it Biblically. We have to allow people to eat clean animals, because the Bible does.