This often ends up in a meaningless discussion where both gets angry. You see, just because your reasons are both moral and great, it doesn't really matter when you want to change people. Personally, I can empathize with the vegetarian cause, as much for the sake of animals as the well as the climate. While I have had the perspective for years, it's not until recently that I have started eating less meat. The reason is not because of climate and animals, the reason is that I have found alternatives that are just as good or better than meat.
For years, people have attacked people who don't get it, done petitions, and done rallies – but here's what I believe should be done: At a point where most people are aware of what's going on, the petitions, rallies, and attacks need to stop. People need alternatives that makes them «want to change» based on their own personal needs and wants. So a great veggie burger, a system for throwing garbage without sorting it (but at the same time it's sustainable), or a plain that doesn't pollute is the way to go. However weird this sounds, there is only up to a certain point that rallies, petitions and attacks can get us.