Your 'raving lunatic' sort of vegans (I wish you weren't so pejorative, but hey, I'll roll with it) are probably expressing deep frustrations about the meat and

Your 'raving lunatic' sort of vegans (I wish you weren't so pejorative, but hey, I'll roll with it) are probably expressing deep frustrations about the meat and dairy industries (many of which are completely valid) at the only people they think they can influence: family and friends. Sorry to hear you've got such a grating relative, but I assure you most vegetarians and vegans don't make it a point to piss people off (unless first provoked); they're just trying to live with the choices they have made. I personally believe in leading by example rather than trying to outright convince anyone that my choices are better.