Pete Buttigieg, mayor of South Bend, Indiana, and 2020 Democratic hopeful, appeared on a Fox News town hall Sunday in which he blasted the network and some of its most popular hosts. Speaking to host Chris Wallace, he explained why he decided to appear on the right-wing, pro-Trump network.

Mayor Pete Buttigieg: “When you see what goes on with some of the opinion hosts on this network, I mean, when you’ve got Tucker Carlson saying that immigrants make America dirty, when you’ve got Laura Ingraham comparing detention centers with children in cages to summer camps—summer camps—then there is a reason why anybody has to swallow hard and think twice before participating in this media ecosystem. But I also believe that even though some of those hosts are not always there in good faith, I think a lot of people tune in to this network who do it in good faith. And there are a lot of Americans who my party can’t blame if they are ignoring our message, because they will never hear it if we don’t go on and talk about it.”

Mayor Buttigieg also called out Trump’s tweets and attacks as “grotesque,” as well as what he called the “media noise machine on the right wing.”

Several 2020 Democratic contenders have appeared on the network recently in an effort to reach Trump voters: Minnesota Senator Amy Klobuchar and Vermont Senator Bernie Sanders, who drew the largest TV audience so far, with 2.5 million people tuning in. New York Senator Kirsten Gillibrand is scheduled to appear on Fox News for a town hall next month.

President Trump took aim at Fox News for hosting Buttigieg. He accused the network of “wasting airtime on Mayor Pete” on Twitter Sunday, and repeated his attacks Monday at a Pennsylvania rally, saying to his supporters, “What’s going on with Fox, by the way? What’s going on there? They’re putting more Democrats on than you have Republicans.”