Brennan has since become an outspoken critic of 8chan and of Watkins, and has actively battled to try to take the site offline. Following the March 2019 Christchurch mosque shootings, in which the shooter posted his manifesto and links to a livestream of the attack to 8chan, Brennan told "The Wall Street Journal" that he no longer wants to be involved in the imageboard world again, saying that "a lot of these sites cause more misery than anything else". Following the August 2019 El Paso shooting, in which the suspect allegedly posted a manifesto to 8chan before carrying out the attack, Brennan called for the site to be taken offline in an interview with "The New York Times", saying: "It's not doing the world any good. It's a complete negative to everybody except the users that are there. And you know what? It's a negative to them, too. They just don't realize it." In an August 2019 appearance on the "QAnon Anonymous" podcast, Brennan said, "If they wanna bring 8chan back online, just be aware, I will do everything I can to keep it down because the world is better off without it."