We must think of the animals.
If everyone stopped eating meat, drinking milk, etc. then farmers and ranchers would have no reason, obviously, for raising cows, chickens and other animals. Currently, every year millions of these animals are bred and raised through out the world, but in the vegetarian model they would have no purpose. It's sad to think about the lost opportunity.
So, eat meat. Give those cows and chickens a chance at a short happy life.