Rational thinking, manipulation techniques (you have to know them to be able to detect them), emotional awareness and stuff like that should be taught at every school. Everybody should be conscious of the fact 99% of what you find online (let alone see on TV) is bullshit, designed to troll and manipulate you and absolutely not worth taking serious (and if something really seems important - check the proofs and don't forget to question their legitimacy). I would even call for the governments to fund efforts to educate every person (adults included) this way - this clearly is a matter of national security nowadays.

I believe there is no sane way (an insane way is to deanonymize and watch everyone - China and Russia implement this) to stop the polarization/toxicicity in the first place, all we can do is develop immunity.