Jon Stewart still can't believe the vitriol that's been spewed at him since he publicly embraced the coronavirus lab leak theory on network TV -- this in the wake of the U.S. government saying it might be legit, but he's far from gloating.

The former 'Daily Show' host discussed the new Energy Dept. findings during the latest episode of his Apple TV+ show. ICYMI, the feds investigation showed COVID-19 might have, in fact, been started and disseminated from a Wuhan lab.

Jon raised that theory during an appearance on Stephen Colbert's show back in 2021 where he ran with what he saw as simply common sense -- namely, the notion the Wuhan Virology Lab might be tied to the start of the pandemic.

JS got slammed for that take ... and now, in reflection, he says he was alarmed by just how tribal the country had become -- politically and otherwise -- and it was evidenced in the sheer amount of rage and hate he got from people he once thought loved him.

He's not necessarily taking a victory lap here, but does hope we can take a lesson from this.

In his view, keep an open mind on things ... especially when, at face value, they make sense. Jon believes that approach is key in navigating modern-world problems -- and he adds, outright censorship is just wrong.