Was Jon Stewart joking about embracing the lab leak theory or was he serious?

https://slate.com/culture/2021/06/jon-stewart-stephen-colbert-lab-leak-theory-late-show.html

Conservatives are taking a victory lap and celebrating on Twitter after the former Daily Show host seemingly embraced the lab leak theory on Stephen Colbert's Late Show return Monday to a full audience. Everybody from Ted Cruz to Tom Cotton to Meghan McCain to Lauren Boebert spent Tuesday tweeting positively about Stewart's rant. Meanwhile, longtime fans of Stewart and The Daily Show were immediately calling Stewart's views "a bit." "So what does Jon Stewart believe?" asks Matthew Dessem. "It’s incongruous, to say the least, to see the onetime scourge of the Bush administration pushing the same ideas as Mike Pompeo unless it’s some kind of a joke, and some Stewart fans on Twitter have indeed concluded he was doing a bit. It’s true that Stewart’s appearance is a stand-up-style riff, but it feels more like jokes about airline food—where the audience is meant to understand that the comedian may be exaggerating but sincerely believes airline food is terrible—than it does a Colbert Report–style joke, where the comedian puts forward a comically stupid argument for something they don’t agree with. In the Bush years, Stewart’s comedy often leaned on jokes in which he pointed out that Republicans were not just telling lies but obvious, stupid lies. Unless he’s doing an extremely subtle parody of himself, that’s the mode he was operating in when Colbert allowed that there was a 'chance' the lab leak theory had some basis in fact...After a commercial break, Stewart returned for a segment that suggested he perhaps went further with his theories than CBS was willing to put on the air. Colbert offers Stewart, seated in the guest chair, the option to 'go on,' and then there’s an abrupt cut to Stewart, now standing, sitting back down again while asking Colbert, 'Can I say this about science?' as though he had been told that whatever he’d just said was not going to air. As with Stewart’s jokes, if the editing is a bit, it’s an extremely subtle one, and not the kind of thing The Late Show usually gets up to. Stewart followed that up with a series of jokes about scientific arrogance, jokes that were both entirely compatible with his earlier statements about the lab leak theory and gave no indication he was being insincere about any of it."