On social media we have these huge conversations where nobody involved has any actual experience. They're just repeating what other people said. Isn't that literally insane?
And when you have a billion people doing this, that's a lot of insanity. Like, world-spanning plague-level insanity.
The ability to learn from other people without needing the same first hand experience is a hallmark of intelligence. It's one of the things about our species that allowed us to develop past just being yet another animal in the wild. Education is largely based on that principle; your history teacher didn't experience the horrors of trench warfare firsthand.
So I wouldn't call social media insanity so much as potentially addictive, which can cause you to overindulge in those behaviours. Admittedly addiction can feel like insanity when you're in the throes of it.
It is not the obvious function of knowledge that's at issue, it is its quality. When the observation and the knowledge get too far apart, the words cease to refer to the observation and begin to refer only to themselves.
And then the quality becomes poopoo. A solipsistic black hole.
I have never verified 99% of the knowledge I read in textbooks either. But aside from math little in the textbooks held much truth. Especially the economy books.