Because such a person obviously has a good heart.
 
Exactly. One who eats meat can have a pure heart just as one who does not eat meat can have an impure heart. In the Buddha’s teachings, the important thing is the quality of your heart, not the contents of your diet. Many Buddhists take great care never to eat meat buy they are not concerned about being selfish, dishonest, cruel or jealous. They change their diet which is easy to do, while neglecting to change their hearts, which is a difficult thing to do. So whether you are a vegetarian or not, remember that the purification of the mind is the most important thing in Buddhism.