Wow. This girl seems just plain stupid based on your description. She seems to be going from "logical" to incredibly ILLOGICAL.
She thinks its wrong for an animal to eat another animal? It is impossible for it to be wrong. Certain animals are REQUIRED to eat other animals to survive...
And I'm sorry....If you can't clean up your pets poop, you should not be having a pet. Who does that?? Who wants cats and then decided oh I don't want to clean up its poop anymore. FIND THE CATS A NEW HOME. Clearly you can't deal with the realities of the world. She should go live in a bubble and continue to eat her cheeseburgers and cry about it.
I eat meat. I like meat. I know where it comes from. I believe humans can live quite comfortably on a vegetarian diet. I even believe that a completely vegetarian diet is actually healthier in the long term. Will I stop eating meat because of this? No. Its delicious! But I'm not going to feel guilty for eating meat. Sure, its sad that an animal had to die, but I have to eat. I have to survive. Plus, bacon. Who can resist bacon?
I'd really like to argue with this girl in person. That would be fun.