That's because "the left" actually believes in the enlightenment narrative of facts and consistency.

First of all, there's this idea that the facts are the narrative. Then the idea that creating narrative is lying, and then an expectation that the narratives will be true, which makes the allegiance of the base vulnerable to "consistency" and "honesty" attack from the right.

"The right", on the other hand (see Altemeyer's "The Authoritarians" for evidence at least within the Western™ cultural matrix - kcurie is not convinced it is a cross-cultural universal) doesn't have a problem holding contradictory ideas in their head (at different times, that is), doesn't have qualms about building narratives, and the base doesn't expect consistency or intellectual honesty from their leadership (they have other values) so their allegiance is not vulnerable to consistency attacks.

When the capital development of a country becomes a by-product of the activities of a casino, the job is likely to be ill-done. — John M. Keynes