Well Hitler is certainly dead, so who cares? There’s no question it would be possible to lie about something like that, though (even if there’s no good reason for it). If you want to waste your time figuring out if Hitler, Elvis, and Jim Morrison are living with their pet Bigfoot somewhere in Argentina, have at it.
I’m talking more about people who insist things are true despite all evidence to the contrary. Like election fraud, the shape of planet Earth, fake moon landings, Sandy Hook, etc.
Most of us accept what is observably and most likely to be true, absent convincing evidence to the contrary, and go on about our day. CTers are prone to believe flimsy and often verifiably false “evidence” because they want something to be true, usually to push a narrative.