What you can't seem to wrap your brain around is that, the people who choose vegetarianism are concerned about issues apart from simply their own nutrition. Millions of people are vegetarian, and you can't walk to them and say "hey, why make the unnecessary effort?". Why don't you study and understand their instead? So many people have tried to tell you the issues that go hand in hand with excessive meat consumption, and you just refuse try and learn to accept somebody else's choice.
Better not start bringing up articles about the health problems caused by meat consumption, because it's going to be loooonggg!