I think that's a misconception. The actions of the brokers protected the brokers themselves and the market clearing infrastructure in general. While all of the retail money was on the long side of the GME trade, and the short side was essentially just institutional money, what's missing is the realization that most of the long side was also institutional money. On a net basis institutions would still be the biggest winners of a price in the $1000s, just that some institutions would be owed billions and other would owe billions, while retail as a whole would also be owed billions.
Also to point out, he's basing his narrative on an outdated set of data. He said short interest was 70m shares, and that was indeed the high of it but on Dec 31st 2020. By mid-Jan 2021 short interest was already down to 60m shares, and then by Jan 29th it turns out it was 21m shares (we didn't know this until 1.5 weeks later). But that means that as the stock skyrocketed on the 27th through 29th, short interest was already making its way down to the 21m shares. Essentially, 27th to 29th was both the frenzy and the squeeze (shorts buying at any price to close out positions). By the end of the week the conditions for a huge short squeeze had already significantly dissolved (not entirely because short interest was still high but not a nuclear weapon anymore).
Then on the options part he talks about on outstanding calls, it is generally uncommon that people actually exercise their money-making options, especially those that are using options to essentially get leverage on their trade which is what most retail investors were doing. So it doesn't automatically generate the need to go to market and buy whatever hundreds of millions of shares he was talking about, because a lot of the options trades will close out without requiring delivery (essentially like futures contracts). And he's also not taking into account delta hedging that any options market makers would already have been doing before on options that had lower strikes and were already deep in the money by the week before.
In summary, cool narrative and his view of the mechanics generally holds up (he owns a broker so he knows more about clearing rules and mechanics than I do) but he's painting the most apocalyptic scenario possible instead of a more realistic one.