Absolutely right, and I would think most people know this. Those that don't or are blaming Biden are either just naive, willfully ignorant or lost in their hate and conspiracies or just trolling.
The Republicans know all this too, and seeing as Trump got elected with this kind of shit only to continue using the same during his Presidency and after and now throughout his reelection campaign, it's not hard to think the story is true and that he and other Republicans on his side don't want Biden to get his way with the election so close.
What makes no sense to me is I personally think they are missing the fact that it could turn more Dem and independent voters away from voting for Biden or voting at all than turn Republican or independents to voting for him.
Also, with no proof this is just a story, but as said before, it's absolutely something Trump and his Republican lackies would do.