Why do vegan people prefer to be vegans ? what are some reason?

This is all that I can think of, hope this assists you.

Explanation:

1.) perhaps to live a longer and healthier life.

2.) perhaps their family tradition is based on veganism.???

3.) To prevent themselves from getting obesity.

answeranovulation;

increases the risk of extinction 

explanation:

the answer is that if the species suffers from the disease, there is nothing stronger than the others, so it is possible to remove wholeness. an example of this is hunger in irish potatoes, which has a deadly disease bearish part of all potato harvest masses. pretty much ruins the land of crops.