You’re comparing different sources, which measure different things: the stats for China are simply stated as “read and write” but the stats for America absolutely bungled in the second article. It’s terribly structured and written, so it’s hard to tell for certain, but appears to sometimes be talking about some sort of reading proficiency in English (which is possibly why California comes out so low).
It's true, I would also like to get the source for US from statista, but unfortunately didn't find it there in hurry. It's not a solid argument to prove Chineses are educated or not, even when we have source with US having higher literacy rate. But anyway, just don't see how can someone simply say Chineses are "largely uneducated".
> the stats for China are simply stated as “read and write”
One could argue that being able to read and write in Chinese is quite an accomplishment. For alphabet-based writing systems, kids as young as 6 y.o. can read pretty much any word they know, and write many of them. Not for Chinese.