I'd like to believe he heard a summary of sword art online's plot and thought it was real

Without hearing the actual conversation, I feel like maybe he was just having trouble describing his thoughts about it. I take it as "disappearing into cyberspace" to mean someone becoming addicted to VR that they don't want to leave whatever virtual reality they're in. And possibly using it so much that the lines between reality and virtual reality become blurred. Or the guy really just thinks people get sucked into cyberspace, I really don't know with people anymore.

I don’t think they were stupid, but they formed a very strong opinion about something they clearly didn’t know anything about.

That's a subcategory of being stupid to be fair

Sounds like they watched South Park and couldn't tell that it's not real.

The average IQ is 100 because it is designed to always have the average at 100%. If magically everyone became exactly 20% better at IQ tests tomorrow, the average IQ would be adjusted and still be 100.

Smart argument.

Good memory is also part of being smart, besides problem-solving and thinking under pressure. But yeah nepo-babies do cause serious problem.

Tho also iq doesn't matter as much. Tests are in a specific branch of math, you can literally study for the IQ test.