[Spooky]

I'm surprised to see that it's only California. Where I live, the vaccine has been made mandatory in educational institutions throughout the whole country.

It becoming mandatory for K-12 is a big deal. The mandate starting in California doesn't really surprise me I guess.

I'm curious why it would be a big deal though. Perhaps this will come out as ignorant on my part, but I would think that mandating the vaccine for schools and universities is just a natural consequence of the pandemic, given how widespread and severe Covid has become. Or is this last part not as true as I believe it to be?

Name a mandatory vaccine that you can still get the effects from.
If you take the chicken pox vaccine, you can't get chicken pox. If you take a tetanus shot, you can't become ill from tetanus, rust etc.
But if you get the Covid-19 vaccine.. you can still get covid at an increased rate? Not to mention the side effects.
So an experimental vaccine made in china is mandatory? With a survival chance of 99.7%?

Yes. That is why it's surprising it is made mandatory for the people most likely to survive covid, with the highest chance of not showing symptoms in the first place.