The issue raised by the article is not Buttigieg's high school experience, the author's high school experience or your high school experience. The issue raised by the article is that Peter Buttigieg is inauthentic: he presents himself as something he is not.
In the history of the United States, carpetbagger was a derogatory term applied by former Confederates to any person from the Northern United States who came to the Southern states after the American Civil War; they were perceived as exploiting the local populace.
No one is arguing that Peter Buttigieg has made "questionable decisions." The argument is that Peter Buttigieg is making extremely calculated decisions while pretending to an earnest, shoot-from-the-hip Everyman who happens to be a former McKinsey consultant who rowed varsity crew for Team Elite from the time before he had pubic hair.