Veg*n Am I just being dumb here or...

Is being a vegeterian/vegan defying the whole object? Sorry to annoy some people but... if we didn't eat meat, would we have cows, pigs and chickens? I mean, there would be no use for them. And we would save a whole lot of greenhouse emissions if we killed cows. I mean, it's part of the food chain to eat meat. If everything was a vegetarian, we would probably die out.

I feel really anti-social now lol.