This one from a year ago. In answer to the question “Why is the education system in California so bad?” I replied:
The education system across the country is a sea of crap with whirlpools of suckitude, archipelagos of mediocrity, and widely scattered tiny islands of excellence.
And it’s that way by design.
We’re into our sixth generation of compulsory public education, and each generation has been progressively (and I use that word with intent) less well educated than the previous.
It’s much easier to lead a population around by the nose if they’re ignorant and apathetic. Henry Louis Mencken noted in the 1930’s:

And why is this?

So the Public Education system was established with all the best intentions! But it brought us to where we are today.
To that I would like to add this, from KGB defector Yuri Bezmenov from about 1983 or so.
It’s not just California. It’s nationwide.
Yes, education has been taken over by the left/marxist and they have both control and acolytes who are slavishly following their directions. The education we got in the 50s and 60s was, IMHO, worlds better than what the kids are getting today!
The US Army has tracked the educational level of recruits since the 1930’s. What they have seen is a steady decline in the average education level of troops, beginning with the Korean War, continuing to today. Those 1950’s era Soldiers were the first to grow up with serious, nation-wide public schooling.