Personally, i respect people`s decision to eat or not to eat meat or animal based products. It could be a personal,religious,health reason or even just plain pickyness, but as long as they respect my eating choices i am chill about it.
I`m a carnivorous dude, but when having a meal with a friend/family member/girlfriend/guest/whatever, i want to make sure they can eat something they like and are comfortable eating.
Ironically, being a picky eater sort of helped me to be more empathic about people`s personal preferences. 
But gotta say i heard stories of preachyness and jerkassery on both extremes of the spectrum, be it vegans/vegetarians, meat eaters or whatever.