From the article: "The United States is a deeply economically unequal society and the proliferation of get-rich-quick schemes taps into a deep weakness in the American mindset."
When has the United States not been this way? The first explorers came over here hoping to find a trove of far East spices or gold, and make a killing. The Spanish did make a killing on gold for quite some years, even as they destroyed entire civilizations. Some American pioneers just wanted a piece of land on which to raise a family and support themselves away from tyranny. But many others were looking for gold or other quick riches. The history of our stock exchanges has been one pump-and-dump after another.
Diehl's other criticism, that crypto mining is environmentally destructive, has some merit, but is that a reason to ban an entire industry? What about people fortunate enough to be near hydroelectric plants, or people with solar electric or nuclear? Building extra coal-fired plants in China to power crypto operations does sound bad, but even China is moving away from polluting sources; they have a desperate need to clean up their environment and they are working hard on nuclear and solar alternatives, not to mention that they are developing cheap, affordable electric vehicles.
Every currency system is built on trust. The U.S. dollar, which is the world's reference currency, is increasingly shaky; last year the Treasury created more dollars in a single year than in all years previously. A lot of people are very worried that a currency collapse from excessive debt and a weak economy is coming in the not-too-distant future.
Crypto currency is an interesting and powerful new technology that may actually save us from monetary collapse; I wouldn't dismiss it as a dangerous boondoggle just yet.
At any rate, I don't see how Mr. Diehl's prescription for banning crypto could possibly be implemented; private companies have the right to create products for sale or trade as long as they are not dangerous. Even tobacco and guns, both known to potentially kill people, are still huge profitable industries albeit highly regulated.