Kid because of expectations. The stronger you are, the bigger the fall when you fail to impress. Look at the list of most disrespected characters in the series: Big Mom, Mihawk, Greenbull, and now Saturn/Gorosei.
Nobody really expected Sanji to be a legit threat to top-tiers anyways, he just beat Queen. Sanji has been doing great this arc for his level and prior accomplishment.