Humility does seem to be the key here. To the extent that they're authoritarian, conservatives generally are more arrogant than humble. They put so much stock in their traditions that they idolize them.

By contrast, liberals and progressive look at history with a critical eye, and don't claim to have absolute foundations for their knowledge. Their knowledge is scientific and tentative.

That humility is a basis for a comedic perspective, since now the comedic task is to mock those who take themselves too seriously. That's what bathos is for, the puncturing of our vain self-images and lofty aspirations.