Thanks for following up. I wrote a long thoughtful reply then fatfingered my screen and lost the whole thing! The long and short of it is, i agree with you that there are many important environmental issues that get ignored. However there are still reasons to belive a plant based diet is more sustainable, even beyond greenhouse gasses. I am planning to write a follow up post specifically on this.

For the marginal case, all I can say is that our outlook is different. I don't believe the treatment of an individual should be dependent on the larger group characteristics. At least not to the extent that excuses compete disregard for the individual.

From a practical perpective, i would probably sacrafice a cow life for a human life, but not so i can have it for dinner when i dont have to. Would i sacrafice a cow life to prolong the life of a brain dead human with no hope of recovery? Probably not.