Not sure what's available online about this but perhaps the question set for this essay is refering to High Noon's position against the genre's conventions in it's time. It doesn't appear to be a film which bucks the conventions now but that is largely because of the influence it had on the genre itself. The Hollywood west was a very different place post High Noon than it was pre High Noon. In particular the image of the western town and its people.
Pre High Noon the western town was shown to be populated by generally decent people pioneering a path in a harsh environment in the face of violent dangers, either from Indians or outlaws. The people of Hadleyville in High Noon are very different. They are selfish, cowardly and uncaring individuals who will quickly turn their backs on anyone rather than stand up to danger themselves. Rather than offer a warm and positive image of american society they represent its darker side, driven by fear and self interest. This, at that time, was very much against convention in a genre which celebrated the forging of a new nation. Likewise, Gary Cooper's character, Kane, is a different kind of hero figure. On the surface he appears to fit the model of the classic western hero; the white hatted hero standing alone against the bad guys. The classic 'a man's gotta do what a man's gotta do' scenario. But if we look closer, his position is very different from the conventional one at that time. His defeat of Miller, by extension, protects the townspeople from future harm but his fight is a personal one and when he leaves town at the story's conclusion it is not because he is a classic loner who cannot fit into modern society. It is because he is disgusted by society's lack of moral fibre. His grinding of the marshall's badge underfoot as he leaves was a shocking statement and an indictment of what had previously been shown as a wholesome and largely benevolent society. Kane, also, is not a classically brave hero either. He is a reluctant one and by no means self assured.
As years went by of course the black and white nature of the western genre changed so High Noon doesn't seem so radical but it certainly stood out in its day and rankled a lot of conservative feathers in the movie business. Its political parallels at the time of McCarthyism have often been discussed although, in truth, I believe it can be read equally easily as a right wing piece as a liberal one. What is not in doubt is that major western personalities like John Wayne and Howard Hawks felt so moved by the insults they perceived in it to make films of their own in response. Showing the west as they prefered top see it. Rio Bravo is a well documented case in point. Wayne was even moved to say "it's the most un-American thing I've seen in my life.
I don't know if any of these thoughts help your friend Lode, but for what it's worth it's the angle I would come from if I was writing the essay.