>>279710935It's an interesting turn because Shinichi is trying to equate the best of humanity with the idea of humanity. He believes that being brave, honest and just is what makes a human human, and not the cowardly cruelty of ganging up on a single dude, for example. He's not only trying to prove his own worth, but he's also making a defense for humanity's case in the process. It makes a lot of sense for a relatively sheltered high school kid from a developed nation to take this course of action.