The textures are one thing, the taste is definitely also difficult. I suspect for many vegetarians you're raised with less umami - the taste highlights for me were sweet things like onions, garlic, tomatoes, salty things like cheese, or just really nicely spiced food like Indian/Mexican etc. Being presented with even the world's finest cut of meat, cooked to perfection by the greatest chef in the world, isn't going to chime with that upbringing. This is part of the reason I've been so disappointed with the rise of vegan menus at the expense of vegetarian stuff in restaurants. You get meat replacement items which are for late converts or part-timers who still crave meat taste, or bland stuff for lifestyle vegans, and meanwhile everyone's dropped the cheese dishes.