PoW is the cheapest way to have secure transactions compared to alternatives. It's not energy wasted - this energy ensures the safety of the global financial system, which is a net positive.
I expected some graphics comparing various alternatives, but instead, it's 20 pages of ramblings, poorly edited.
I'm sorry that people are making free (as in beer) content in their free time (which ain't free) that you do not consider aesthetically pleasing.
I think he meant he expected you to link to something more explicit and objective, such as a scientific survey of the various options, and not that the author of that link should have done better.