I'm pretty sure the author is specifically referring to the framing of P vs NP used in the video, not to the problem itself, since a bit into the article they write this:
"I think that the framing with inverting a function f is quite underrated."
"I think that the framing with inverting a function f is quite underrated."
Of course, using the title "What P vs NP is actually about" is a bit of a stretch -- "Interesting take on P vs NP" would be more honest.
I think it's just that the first time you use underrated, it seems to be referring to the problem itself, not to your specific take. With the video as context, or even just reading a few sentences in, the meaning is clearer.