If you look at the moral side of things, vegetarian recipes still often require products from the animal industry. If you look closer at the ways animals in those industrial settings are treated, it can be hard to stomach. We like to believe the images of happy cows on mountain pastures and chickens running around freely on a farm, but the reality looks very differently in the overwhelming majority.
Plus there is still the environmental issue, using food to raise animals to produce food is still a lossy process.