Vegetarianism doesn’t involve killing of animals.
but, plants are also living and they too have feelings!
Cutting of plants doesn’t cause killing. Removal of terminal parts of plant acts as pruning and will enhance its growth!
Can we decide that the death of the animal and growth of the plant are good? When an organism is dying, its energy is being transferred to higher energy state and that phenomenon is a part of nature.
The organisms die even if we don’t kill them. Then also they travel through natural energy cycles. If we kill, we are interfering with the nature. Of course, the other organisms do kill lower organisms. But, Man has no right to do that because he has got the intelligence to understand and protect the nature!