Grayson Wentz — the St. Bernadine's student expelled by Mr. Gesualdi — started working at a phone repair kiosk in the mall after getting kicked out of school, where he toiled away day in and day out, burning with resentment for his former classmates and the faculty. When a pretty college student named Abbey Samuels comes to his kiosk to get her phone fixed one day, he unlocks it and steals a ton of her photos and videos that he later uses to catfish vulnerable people at St. Bernadine — going by the name Brooke Wheeler.
Grayson is furious at how the kids at St. Bernadine pretend — in his opinion — to have such perfect lives on social media, even though they're "f*cking fake" and "f*cking plastic" in real life; his streak as the Turd Burglar begins as a way to show the world the "real" people behind those smiley Instagram photos. His final act as the Turd Burglar is to post all the graphic, private photos and videos he got out of people like Jenna and DeMarcus, even though he promised he wouldn't. In fact, Grayson also catfished Drew, by the way, which is how he got those photos of him in the diaper. When Drew refused to participate in the poop pranks, Grayson released the photos (as well as a wild naked video of Drew during the "dump").
In American Vandal's season two finale Grayson is seen on trial for multiple crimes. Mr. Gesualdi has his teaching licence revoked, and Jenna Hawthorne and DeMarcus Tillman both get community service (DeMarcus also escapes Lou's hold on him and decides to play basketball at Villanova). Kevin has his felony counts reduced from three to one, but is sentenced to nine months of house arrest because he was not blackmailed into perpetrating the Brownout. He says at the end of the show that he's enrolling in a public school for his senior year, and has high hopes for his future.
It's a far darker ending than the conclusion in season one, but it holds an important lesson about social media. As Peter notes in a voiceover in the final few minutes of the episode, "We're not the worst generation, we're just the most exposed."