A few months ago, a relative of mine (a high school drop out, but I'm sure that is just a coincidence) shared a post on Facebook. It was littered with typos. It referred to an "MRNA virus" (caps in original). It claimed that the person writing the post's husband is a microbiologist and has worked at many "renoun institutes" and had "made science better" and was involved in making vaccines, but warned that Covid vaccines were part of a plan to control Patriots...
It was like 4 paragraphs long. It read like a 9th grader had written it. I corrected all of the science errors in it, but I was told by one of my relative's friends that it "looked right" to her.
The share on my relative's FB timeline got HUNDREDS of likes. A few weeks ago, I searched FB for keywords in the post, and it had been shared by dozens of people, including on some chiropractic pages, health guru-type pages, and even by a couple of nurses. I did my best to report the posts for false claims about health. But I checked a few places last week, and FB left them up - not even a warning. FB doesn't want to upset the ignorant, you see.
So yes, a lot of people are brainwashed.
Just not in the way you seem to think.