There is nothing wrong with eating meat. Some people think it is wrong how the meat is raised, but that is understandable.
If humans all convert to vegans it will deplete the land fertility and all the unkilled animals will cause massive environmental disaster. Look at India its a hell hole where cows and all kinds of animals shit on your doorstep
Wrong. Farming livestock does much damage to the environment on all fronts, and cows are sacred in India that's why they roam around.
Wrong, Cows produce higher carbon footprint that all cars trucks ships and planes on the planet combined
Killing animals helps protect the environment
I'm aware of the first part, but you're wrong on the second. They produce more because of the sheer amount we raise and breed. Killing them doesn't help if we continue to farm them this way. It's not really sustainable either.