Yes, I really think Peterson meant what he said — I believe he was making a hateful comment about a woman because of her weight. Of course he was attacking her personally. That’s what his tweet was, a cruel personal attack. If his judgmental tweet carried some other message besides the cruel personal attack, it was, on its face, still a cruel personal attack.
I’ve lived all over the world, btw, and I’ve personally experienced cultures in which heavier people are considered more beautiful than thinner people. If you don’t know that’s true, google it, because it is.
You’re wrong about the staff at Sports Illustrated. I guarantee some of them have internalized different cultural beauty standards than you have.