When something like 50% of likely Republican voters believe that the election was stolen from Donald Trump (on the basis of no evidence), that the problem is worse on the right than the left is well-documented. That there are massive numbers of people on the right who are (willfully?) ignorant of critical matters of fact is actually the state of affairs.
This is not something about which people should have reasonable doubt: the claims of election fraud have failed to materialize over and over and over again.
It doesn't mean that they're confused about everything, but this is the kind of thing that is very important to get right, and they haven't. It's gross negligence.
Dustin didn't claim that people on the left are immune, just that they're less affected. I think only some of his reasons are likely to be correct, however. If anything, he's too kind to the right. (He's also too kind to the left.)