K-12 was mostly a time waster.
Training the mind in the techniques it needs to navigate life starts well before K, and if they are not installed early it is all but impossible to re-program a brain later.
If parents fail in their initial duty, it is very hard for a stranger to instill critical thinking in a personality that has settled into id-controlled behavior.
Before readers pounce on my "re-program a brain" statement in relation to the current social/political situation, I will say unequivically that rampant falsehoods and conspiracy theories are successful because they fill a void that has existed all along. I would suggest that these voids tend to manifest emotionally rather than intellectually, and leave people feeling vulnerable and helpless - ripe for harvest.
On the other side, people with critical thinking skills do not need absurd bunk, and recognize it instantly for what it is.