this is such a... wrong conclusion to make from the study. the study has found a correlation and by no means is it a causation. there are so many cultural, societal reasons for this to be the case. (eg. in india, upper caste people are usually vegetarians who generally have more access to education.)
the parent comment was basically creating a causational logic for why vegetarians are more likely to be "smart"-er. which is not true.
Also, what's your point? Is there a proven direct correlation between ethics/morals and educational level? And even if there were, does that imply that this less educated group is as a whole completely wrong? And are you implying that ethics and morals were even objective and measureable? I mean, completely no idea what you are getting at here.
Vegetarianism selects for openness and analytical/reflective thinking but the extra step to veganism selects for absolutism/purity and rigid category-based thinking. Reflective thinking and openness are definitely correlated to IQ so I believe the result in the article.
The point here is to know your audience. The people on this site are perfectly primed to respond well to a vegetarian/environmental point of view.
I don't follow how you conclude this at all. there is nothing to indicate this is the case.