not to mention that hashrate changes are so much more complicated than just being affected by the price.
I agree that the article or in fact, most articles from that website are b.s, Ignore the rest of the article, i only referenced it to save myself the trouble of explaining how the hash ribbons indicator works.
Now it is up to you to believe or disbelieve that miners capitulation is a huge factor which effects price directly, this is is not a matter of a single coincidence or a few random events, it is simply humen psychology , just like the fear and greed indicator.
Miners bet on bitcoin price to go into their favour, and since the majority of miners lose money just like how the majority of traders lose money, it is essential to know when all of these people are capitulating because that is when the market is about to make a shift in direction, and of course, when they are optimistic and going all in, it is time to leave.
Having said that, this is yet another indicator which is subject to failure just like any other metrics people use to estimate price.