The article’s point there was that the average Joe’s actions under the current mortgage system could make sense, if they were based on a deep understanding of financial markets (including the subtleties of options trading) and were betting on increased volatility of interest rates.

If the sentence doesn’t make sense, that’s arguable part of the point: the author wants you to react, “huh, average people don’t think like that, so of course that’s not a rational bet”, which is his point.

But if you want to understand the volatility/gamma dynamic and strategy the author is referring to, this gives some detail. I’ll summarize it myself once I catch up and feel I understand it.

https://seekingalpha.com/article/181382-option-strategy-long...

This isn't a news article. It's a newsletter that targets people who care about finance and everything else, but definitely finance. Rates vol means volatility in rates of interest. Long gamma means has investements for which the thesis (bet) is that gamma will rise, whatever gamma is.