In my experience, and in particular with conference food, vegetarian dishes has its own food culture and tastes. To be specific they usually do not include any pepper, garlic, chili, or herbs like parsley, sage, rosemary, thyme and cumin. Salt and umami is also often missing. Instead the cooks tries to create tastes through using different grains, seeds, fruits, salads and vegetables. Food without meat does not have to follow that culture but it is a bit like telling thai cooks to not use fish sauce, cilantro and chilies.

For me if food without meat want to raise a larger audience it must first be separated from the vegetarian food culture, because not everyone like the taste of that food culture.