I don't think I could date a preachy vegetarian. If she had a problem with my food consumption or whatever and was always nagging it wouldn't work. If it was a personal choice, that's fine, whatever.
I'm married and don't date so this is just like hypothetical or whatev
Story: When I went to Colorado to visit J-Dub, we went on a hike, and after we went back to our cabin we had rented for a round of delicious Black Cherry Frescas. J-Dub's ex GF picked up the can and started reading the ingredients before she opened it. I don't like stuff like that. Just say "No Thank You I'll have a water" and don't make it a big thing.