Sabroni, when I cook for vegans, it's vegan. I eat vegan probably 3 days a week. But when my sister-in-law shows up without so much as a by-your-leave, sticks a spoon in my bean pot & takes a bite without asking, am I at fault that she is happily chowing down on legumes cooked in the drippings of a wild turkey or boar that I smoked the night before? Or that the soup was started with fat-back? Or has proper veal stock in it? Or the time she commented that the turkey breast chunks in chili verde were the best tofu she ever ate? Keep in mind that I don't ask her over, rather she inserts herself. If it were anybody but my Wife's sister, I'd ban her from the property for her rudeness.
If you (or any other sanctimonious vegan) were to offer me roast pork, I'd bow out gracefully knowing something was badly wrong with the situation. Not that I'd ever break bread with you, that is. Life's too short to spend time with the holier-than-thou set.