I've heard this, but I don't think this is actually true (save for some other services that target children).
The problem isn't just the content, though. It's also the medium. SFV as a medium cripples cognition and attention span. It feeds bad habits, emotionally and intellectually.
How many of Gen Z/Alpha have the attention span to sit through a movie, let alone a book? There's even a joke that if someone says they've binged on a Netflix show, it means they're a millennial: younger generations would find that kind of sustained engagement with a subject boring.
SFV is opposed to the kind of engagement you need for deep work.
They deliberately made SFV educational content only. Tiktok had to comply or face the wrath of the CCP.
SFV about a math theorem or a physics phenomena or explaining how to use a type of conjugation in English? Cool.
SFV thats just a clip of a show or movie with some stupid music overlayed? SFV about a kid doing some stupid dance? Banned.