February 26, 2015 11:53 AM EST

Jon Stewart finally offered some more insight into why he’s leaving The Daily Show.

He opened his show Wednesday with clips of Republicans reacting to the news of his departure, many of them accusing him of distorting facts. After challenging Fox News to a “lie-off” and playing clips of some of Rush Limbaugh’s more controversial comments, including calling a girl a slut and saying white people shouldn’t feel guilt for slavery, Stewart got to the meat of his argument.

“Take it from someone who’s been watching what they do for a blessedly almost over 16 years or so,” he said. “Their chronically angry war for ideological purity, where every aspect of life becomes a two dimensional battle for America’s soul—it ages you. Even watching it is killing me.”

Watch the full clip below:

Write to Tessa Berenson at tessa.berenson@time.com.

Read More From TIME

Related Stories