Many loath hunting but eat plants with little thought. How do we know for sure what feels pain, what does not, what forms of life are more worthy, what forms less worthy? I remember a study I read where they took two plants and separated them in different rooms then tortured another: the one untouched reacted to the torment.
I do think giving more respect to what seems to be the highest lifeforms: sentient from our perspective, is the wisest course. But we must always remember we may have it far more wrong than we think we do.