Because democrats value egalitarianism and education. Good education is expensive. The businesspersons that have expended the most effort to offshore our jobs to the serious detriment of working-class America have had some of the most expensive and exclusive educations of all, and they are some of the wealthiest people on the planet… (conservatives fullstop here and ignore the rest: …who are also likely voting conservative). Couple that with the fact that expert (educated) advice and direction is often in direct conflict with the myopic goals and views of the uneducated. Don’t dump shit everywhere (but it’s cheap, easy, and fun to roll coal and pour used motor oil on the ground!), don’t cut down all the trees (but mah lumber is more expensive!), and maybe wear a mask (grandma was gonna die eventually anyways, at least I can bring her Covid from the Applebees take out!)

So it’s really easy for the conservatives to paint education = evil, and then of course they couple that with feel-good bullshit like “common sense” and small-town American wisdom that is completely meaningless but makes the uneducated feel smart or like they have control of their situation.