Leftists are more than aware the election could be rigged. A few were even making that argument when George W. Bush was reelected because they couldn't fathom how he got reelected after 9/11 and the Iraq invasion.

While people with TDS just assume the country came together to get rid of "Literally Hitler," others may think there was fraud but either don't think it was enough to change the results, or they are unwilling to say anything because the alternative is four more years of Trump and possibly the senate being 54-46 (when you consider that fraud probably cost us a seat in both Arizona and Michigan, as well as both Georgia seats).