The idea that Xi is functionally illiterate beggars belief and is clearly false. It's not impossible his actual Chemical Engineering education was of low quality, but to say he is close to illiterate is actually silly.
Also have you seen the people coming out of majors these days (and by that I mean my own graduation class of ~2010)? Uni access expanded so much that just graduating doesn't mean that much anymore. Especially for career government officials who probably went straight into government from uni with no work experience.
Xi got into Tsinghua not due to intellectual ability, but due to his political connections with the CCP. This isn't the meritocratic or technocratic story one might have assumed to be the case reading the above comment. China is ultimately a poor country on a per-capita basis and essentially a failure when compared to countries with a similar culture and historical circumstance like Taiwan. It's only their massive size that leads people to the faulty conclusion that they have anything worth emulating.
I'm fully willing to accept that he got into Tsinghua from connections, and at the time I'm sure there was mass instability and on top of it I'm sure he would have been able to avoid coursework if he wanted to, leading to the real possibility of low quality education. That's still far away from being almost illiterate.