Nice article. Just an opinion, but I believe the NFHS rejects the concept of "instant replay" because they realize, despite all the fanfare and spectacle, HS Football although a terrific and exciting game, is a game played by HS student-athletes and not a matter of world peace or US Supreme Court attention.
Even the very best coaches make errors in play selection, personnel assignments and general judgment. Even the best, most serious and attentive players fail to execute their assignments in critical assignments and officials sometimes fail to see everything they're expected to. Part of this great game is guaging how a team responds to adversity, how it deals with errors by coaches, players or officials whose judgment, about the relative impact of some technical violation is, or is not, material to the conduct of the game.
John Madden is rumored to have opined, "a major difference between officials and coaches is that officials are not graded on who wins or loses", which is a significant, and important, distinction.
Perhaps the NFHS realizes that regardless of how significant any High School Football game might seem, it's likely a minimum of 500 Million Chinese, really couldn't care less.