I get your sarcasm. The sad thing is that there are many studies that show that eating fat does not make you fat - sugar is the real culprit. So replacing fat with anything is just deceiving the customers. Especially when corn syrup is just another kind of sugar.
Sources:
https://www.businessinsider.com/eating-fat-wont-make-you-fat-sugar-will-2018-7?r=US&IR=T
https://www.livescience.com/10079-difference-corn-syrup-sugar.html