Excessive extreme behavior does great damage to the environment. Growing vegetables requires pesticides or some drugs to drive away pests. Even organic vegetables are difficult to achieve 100 bar with little pesticide.

Among vegetarians, vegetables and plants do not belong to big life, even plants in science belong to life. Because the vitality of plants is relatively weak compared with animals. So plants are not complete life.

Ruthless sentient beings are Buddhism's classification of plants. In other words, plants have no clear feelings, even pain. Soul theory is not a primitive Buddhist view, so it is impossible to comment.