For me I am a vegatarian because I do not want to harm sentient beings. I realize that plants have a life force in them as well, but I see it as that animals DO suffer more than plants and since we DO need to eat I will try to eat food that causes the LEAST suffering/harm to other sentient beings. I also do not agree with the way animals are treated in their lives (cramped quarters, fed unnatural foods, overworked, etc) just so I can enjoy a burger. I can find many other foods that satiate me and cause less harm.
I believe we are all interconnected and everything we do impacts all. SO I am mindful in the choices I make not only for others although I am FAR from perfect.
I believe in this day and age the way we live we do not NEED (maybe want) but we will not die without meat in our diets
I do not believe to eat meat that it is our given birthright. I know people quote religious texts but my personal opinion is that I want to cause the LEAST amount of suffering to any being..and animals definitely feel more suffering than plants.