He was last averaging 129K viewers per episode in the 18-49 demographic, I'd say that is a far better "excuse" than a threat from the FCC. As if DIS doesn't have a legion of attorneys. Give me a break.
More importantly, his viewership didn’t suddenly change and the cancellation came about pretty clearly as a result of the FCC threat and not any business decision the company would have made otherwise. Not a lawyer but I would think that Kimmel has a 1a lawsuit he could bring against DIS and the government.
https://latenighter.com/news/ratings/late-night-tv-ratings-q...
I'm not sure if you think people are extremely gullible, because one would have to be in order to buy that line.
If there's a threat going on, and an another excuse the threatened can blame, the threat is no less potent.