This exactly.  You know that lardbarge feels even worse about its body than you do, despite your insecurities, and that's the reason it's barbing you with those comments that even it can't possibly believe are true.  It just assumes you won't/can't respond in kind because its fat privilege in society makes it taboo to call fats out for what they are: disgusting creatures with no self control.    It started it, it asked for it, and all it takes is for you to respond "well at least I'm not fat" and it'll crumble like an overdone cheesecake.