It is not reasonable to tell someone to quit eating meat. If everyone killed themselves it is better for the planet.
No, but they shouldn't think it is a big impact either. Let's keep it honest.
When you choose to help people instead of cows, it is not just for the people but also for the world and future generations. But helping people is better than helping cows.
I really don't care what, if any, gesture people make toward making the world a better place. What I don't like is someone telling me that their way is better than my way, especially when they still eat meat on occasion because it tastes good, or because the meat they eat had a marginally better life. Seems hypocritical.