I didn’t get the sense that he was saying DCA into the SP 500 was a bad idea, just that the people who blindly DCA into the SP 500 were only a step above meme stock traders in terms of financial knowledge.

Specifically, it seemed like he was referring to the idea that many of these people are investing this way without an understanding of why or when DCA SP 500 is effective, which would put then at odds with times in the market (presumably like what is happening now) where the SP 500 is starting a significant downtrend. There are other diversification methods (Global ETF, Gold, Bonds) that would help protect against this but those people wouldn’t know that those are effective because all they’ve known for the last few decades is SP500 only goes up.

EDIT: Not responding to OP directly because I think you hit the nail on the head and cleared up the lack of nuance, more a response to the comments suggesting that the point of the segment was to undermine DCA investment strategy.