You answered your own question. Live and let live is best. I try not to assault the character of canadrocks, no matter what he says, because he has to live with himself 24/7 and that is punishment enough.
Fat people develop rationalizations and excuses and aggressive replies, but they KNOW inside what they are and outside advice bounces off them. I think it only hardens their armor.
Lastly, I learned that when I criticized others, it was likely the same behavior in myself that I was ashamed of. So, rather than to be nasty to others, I was better if I worked on fixing myself. Not easy but well worth the effort.
Incidentally, I admire what you say on your page. :-) You would be a quality friend.