The article is specifically saying that in instances like yours, the problem isn't the large demand driving up prices - it's that businesses are driving it up even beyond the natural demand price having been emboldened by the former.
This is a fabricated sequence of events. It's the SEC/CME/FTC, etc's job to verify the following in this example: 1. Did Home Depot raise their prices _more_ than was necessary to respond to increasing consumer demand and decrease supply? 2. Did the suppliers stockpile or falsely report their availability to result in over charging? 3. Did pricing between sawmills/loggers and suppliers increases proportionally? Did pricing between retail and suppliers increase proportionally?
These questions will help to understand possible unnatural inflation was introduced. In the sequence of events the sawmill behavior is just a single indicator along the way.
When people stop buying what they’re selling, we know the product or service isn’t worth it, so the price comes back down.
When you're selling something people need to survive, like food or medicine, your moral imperative runs in the other direction, and profiteering at the expense of deep need is immoral in the extreme, especially if there are factors preventing competition so you have a captive market, like increased corporate concentration or a government-enforced monopoly.
You won't find it in Marx, Keynes, etc.
The only reason capitalism isn't 100% broken is because of regulation. Therefore we must accept that pure free market forces are not the morally superior path.