I'm not American, but a lot of this, especially the "Helen Keller wasn't deaf/blind" and was a "Nazi terrorist" doesn't seem like a failure of the education system, but more how much social media influences what we believe. The "Helen Keller is fake" conspiracy has been going viral on TikTok for a while now, and calling people "Nazi terrorists" is the 'woke' thing to do on places like Twitter.
And on the recording topic, the teacher is the only person in the video who you could identify. The children are all anonymous and I don't think it was ever posted to dunk on dumb teenagers, but to point an actual problem. You've also only got 45 seconds of video from, what I assume, was probably a 50-60 minute class. The kids very well could've been corrected.