I watched a documentary on the History Channel a few years ago about Reagan’s landslide win against Carter in 1980. It was something crazy, 480+ electoral votes for Reagan. But the funny thing was that crowds of Democrats believed then and still do now that it was an unfair win because Reagan somehow colluded with the Ayatollahs to not release the hostages.
There was also this nutso theory that Bush Sr won in 1988 because of “racist” Willie Horton ads. It’s been repeated as true as recently as three years ago, which is how I learned about it.
More recently, the majority of Democrat voters believed as recently as 2 years ago that “the Russians” actually changed the voting tallies in 2016.
I’m not even mentioning the Gore disaster that went on until mid-December in 2000.
Based on this evidence, I’d say that the Democrats who mock Republican voters for not accepting the razor-thin margins in the current election are being a tad hypocritical.