Thich Nhat Hanh was asked “Why vegan rather than just vegetarian?”
“We don’t want to eat eggs, and drink cow’s milk, and eat cheese anymore because raising cows and raising chickens creates a lot of suffering.
If you have seen the suffering of the chicken, the suffering of the cows, you would not like to eat chicken, eat eggs, drink milk, or eat cheese anymore. It seems the system has been contaminated.
So to be vegan is not perfect but it helps to reduce the suffering of animals.
There are films made about the suffering of animals. If you have watched these films you will see. We should eat and drink in such a way that preserves compassion in our heat. We should consume in a way that helps to reduce the suffering of living beings and that way we can preserve compassion in our heart.
A person who does not have much compassion in his heart cannot be a happy person anymore. And that is why I think everyone has to learn how to reduce the eating of meat and the drinking of alcohol. “