Here's my logic. If I fall in love with somebody, odds are I will ultimately seek to marry said individual and live with her. If we live together, odds are we would desire to share meals as a family; after all, it is usually easier to cook up one kind of dish en masse than two entirely different meals. If this special someone was a vegetarian, and myself having a rather carnivorous palette, this would inevitably cause friction. For the sake of a stable household, I would be hard-pressed to pursue such a relationship.