I mean, I doubt he knew anyone who speaks Chinese or was arsed to do any research. “Simplified Chinese” does sound on the surface level like they just dumbed down the language, so I’m assuming he just ran with that assumption because it’s convenient for his narrative. A more accurate and less ambiguous term would be Simplified Chinese Script.

By the way, Korea went through the same thing. Korean used to be written out using Chinese script. But the language structure of Korean wasn’t served very well by Chinese characters, because Korean is an agglutinative language while Chinese is an analytical language. So they made their own script that’s specifically designed for the language.