“that the Mueller report has barely put a dent in the lefties’ belief in collusion. “
They never believed there was collusion. That was a plan to divert resources away from exposing their collusion.
Depends on which leftists you’re talking about. Those at the top know there was no collusion. But the followers believe what they’ve been told by their leaders and the media, which is that Trump colluded. The other poster’s coworkers still believe it, and in my opinion they are typical.