Nobody is obliged to learn that many languages well, but truth demands scruples. If you are not interested in truth, what is the point of publishing one of these?
The result is predictable: whichever language the author already knows best wins.
In this one, for example, we get:
"There’s obviously a lot more pushing you could do with C++. However, I suspect it would end up getting more and more low-level and more C-like"
which is just wholly false.
There are reasons why the people who are the most serious about performance use C++: you can get C++ code as fast as the machine can physically do without giving up any abstraction or readability, and without avoiding powerful features. That is the core value proposition of the language: abstraction without penalty. It delivers, and not by accident.
To get top performance does require awareness of what operations are inherently slow for machines, and not writing code to require such operations. But that doesn't mean giving anything up.
Code that looks like C is no faster than C. Hence, to make code faster than C, you must make it look less like C.
Really, we don't expect an article like this to reveal all about how to write the best code in all languages.
Just don't report lazy falsehoods.