"So I Started Eating Meat Again..."

This seems to be happening a lot. Vegan/vegetarian tries the paleo way of eating and promptly sees dramatic improvements in health:

"...My decision to eat meat again was driven by health concerns. I was a vegetarian for over ten years and I did so primarily for ethical reasons. It was in the last several years of being a vegetarian, however, that I grew increasingly concerned about my health. An increasing number of studies started to point at the importance of meat protein and animal fat—not to mention the perils of soy (which was a staple for me). Moreover, my performance at the gym was stalling. My energy levels were consistently low and I was making very little gains. This was an indication to me that something wasn't right.

"So, after a decade of avoiding meat, I was curious to see if a reintroduction to animal protein could change the situation. I switched to the Paleo diet and within three months my BMI went down from 17% to 12% and I gained nearly ten pounds of muscle mass. I was astounded. And add to that an improved sense of well-being, mental clarity and energy— I was sold. My experiment with eating meat exceeded even my own expectations.

"Now just because I'm eating meat again doesn't mean I have to be an asshole about it....

  That's nice, but you're still being a bit of a dick about your eating choices:

"...Well, unlike many other carnivores, I'm at least cognizant of the fact that I'm exploiting animals for my own well-being. While I have made the move to a diet that contains meat, I am not completely at peace with it. I am fully aware and respectful of the fact that the meat on my plate comes at at price, that being the life of another animal...."

Unless they're complete idiots, all carnivores get the fact that they're "exploiting" other animals.  By definition, that's what carnivores do.  And the fact that you are "not completely at peace with it" just means you're still being foolish, not that you're morally superior.  Smug self-satisfaction is dangerously close to being an a**hole, btw.  Just an observation.

"While I agree that many meat eaters can be obnoxious, inconsiderate and self-righteous in celebration of their carnivorousness, there is an equally pernicious sentiment among vegetarians that needs to be called out: the false notion that a vegetarian or vegan diet is actually good for you. Like the meat eater who needs to acknowledge the harm they're meting out as a consequence of their dietary choices, the vegetarian needs to acknowledge the fact that their diet is far from ideal...."

I have never met a single non-vegetarian/vegan who was "obnoxious, inconsiderate and self-righteous" about their eating choices.  Non-Indian vegetarians seem to have this market cornered.  Most omnivores never give the fact a thought.

"...A vegetarian's choice to avoid meat for ethical or environmental reasons is truly noble. They are willing to sacrifice their own health in order to mete out as little harm as possible. I bow down to these people in deep and profound respect...."

It's not really noble.  While I respect folks like the Jains who have a clear philosophy that leads them to vegetarianism (not veganism), I don't share it.  Vegans, on the other hand, are just foolish.  Like people who play Russian roulette are foolish.  Malnourishing yourself and your children does not make you morally superior, period.  I've never met a non-Jain vegan or vegetarian in American who could offer a rational explanation of why their diet was "noble".  That's not a good sign.  Most go on about how humans didn't evolve to eat meat, which is just flat wrong.

"...But that said, vegetarians should not claim that their diet is optimal—because many of them do. The avoidance of meat protein and animal fats, plus the heavy reliance on soy and carbohydrates, is far from ideal. As a person concerned about his health, and as someone who feels that there are reasonable ethical options available for meat consumption, I have consciously (and perhaps selfishly) chosen to avoid a sub-optimal diet. I have come to recognize the fact that the human body evolved to eat meat, and that in order for me to live and be at my best, I need to be an omnivore...."

Good for you.

"...Lastly, as a bioethicist who has strived to walk-the-walk, I am increasingly coming to grips with the fact that I cannot live an ethically or morally perfect life and that I should stop trying.

"As for my animal rights advocacy work, that still remains a top priority. I'll continue to push for better conditions at factory farms (if not the elimination of factory farming altogether), the development of cultured meat, and of course, extended rights for nonhuman animal persons...."

You're still hung up on this idea that eating meat means you aren't moral.  That doesn't make sense.  Carnivores exist on the planet just as surely as non-carnivores do.  One's not "good" while the other's "bad", they're both just living as they were intended to.  Humans evolved to eat meat or were created to eat meat, depending on your point of view.  It's going to be a difficult circle to square, advocating "extended rights for nonhuman animal persons" while eating them, but good luck on that.  (Nonhuman animal is redundant, btw.)

"...For my vegetarian and vegan friends and colleagues, I hope you understand and continue to support me and my work...."

Definitely good luck with that.  As Lierre Keith discovered, no cult is less forgiving of apostates than confused Western vegans and vegetarians.

But if you can drop the attitude, we'd be happy to welcome you back to the human race.