I think most people on the left like the real science-based facts, as opposed to "alternate facts" that are made up to spin events. So they tend to not believe in silly conspiracy theories.

Now this is not to say there aren't actual conspiracies. For example, Hillary talked about a vast right-wing conspiracy, and it turns out it was real: Republican spent decades and many millions of taxpayer dollars investigating her, and they never found anything to charge her with. That certainly sounds like a "get Hillary" conspiracy to me.

As for Trump's Covid-19 immunity, it could be that when he made the emergency trip for medical care a few weeks ago they gave him some monoclonal antibody or some recovered donor serum antibody. That would also fit with the timing of his claiming he was taking hydroxychloroquine with zinc. I'm sure he would get the best, most expensive treatments possible, and not be sent home to see if he got pneumonia.