I'm going to comment on the general issue, not on the specific link.

I'm a carnivore, so what I'm going to write is my best approximation at purging my reasoning of cached thoughts and motivated cognition.

I'm not convinced that present-day vegetarianism is not just group signalling.
Of course you wouldn't want aware beings to suffer pointlessly. But from there to vegetarianism there's a long road:

• you should at least try to argue that it's best to never be born than to be born, live a few pleasant years and be killed;
• that me not eating meat is the best way to stop animal suffering, all else being equal, rather than say lobbying for passing a law that prohibits intensive farming;
• that not eating meat wouldn't hurt humanity in the long run (the fact that vegetarians need creatine supplementation to be intellectually on par with carnivores is especially frightening for me).

All these points are taken from granted in the article, but they are far from being so.