The difference is Chance made no claims that he was in perfect health, and outright admitted that he was having issues with diabetes, mobility, etc. He was openly aroused by the idea of dying from his obesity related health problems, and got his wish.
Kelly denies that her obesity is the cause of her health problems, and truly believes that you can be 100% healthy with organs smothered by a foot of gunt.
I think the new "feederism is actually based???" arc could possibly be Kelly attempting to cope with bedroom issues. Why bother with PIV sex when you could just cum from eating 2 buckets of Sleepytime Chicken?