I think a big difference between leftist way of thinking and conspiracy theorist way of thinking is the following:

Conspiracy nuts see "the elites" as this grand, mysterious, near all-powerful group of superhumans basically. They clearly view them as inherently superior for them to be able to weave these grand conspiracies together. It ties in with the average right-wingers hierarchal way of thinking, where many of them know that they'll never be billionaires themselves but they're still willing to fight for them, because they think they deserve it, they're just superior people in their mind and and them being at the top is just the natural way of things. That's why conspiracy nuts believe these outrageous theories, because in their mind the elites are capable of literally everything.

Whereas leftists see the elites as idiots just like the rest of us who exploited others to get to the top, or just popped out the right vagina. We know they're normal people who couldn't engineer a coronavirus conspiracy if you gave them a manual for it.

This theory is based on nothing but armchair psychology and it's pure speculation so take everything with a grain of salt but I'd be curious to know what you guys think of it.