Ok, but that makes it just as poor of analysis as they're engaged in, doesn't it?

Meh. If peeps, from your grandma to the opinion pages of the major newspapers, can do unscientific attribution studies on the fly every time there's a noticeable weather phenomena or, say, unvaxx deaths, I can do the same for vegetable eaters.

On the upside, it has the added benefit of annoying them greatly and dispelling their beliefs in self-virtue 

denlillaapan

HealthAndFitness

My friend is eating an almost vegetarian diet. I think it's killing him.

Signal312

This is why I say "seeing what you want to see". We didn't hear anything about those other factors and yet you're comfortable with this conclusion. I didn't hear anything that makes it sound "most likely". I heard about someone with a healthier than average diet (less processed foods, less added sugar, etc.) who's suffering more than average infirmities. Nothing about that points to diet as the most likely culprit.