What’s involved here has nothing to do with the issue of vegetarianism.
A good managing editor respects the fact that his readers represent a variety of opinions and that they should all be respected even if the editor disagrees with them. (He’s an editor, not an opinion writer.)
If the editor doesn’t want to use an article or suggestion sent to him he can ignore it or write something like: “Thank you for thinking of our publication but unfortunately we can’t use your article at this time.”
I once sent a letter to the editor of another newspaper offering well-documented evidence that mammograms may harm more women than they help. The editor sent me an email reply accusing me of not caring about women who get breast cancer! Not only should such an abusive editor be fired but I probably should have sued him for libel!