It doesn't matter who thinks there was fraud. In 2016 it was the Democrats hollering fraud, stolen election, Trump was an illegitimate President etc. And I suspect there will be all kinds of challenges to the votes in this election too, maybe on both sides.
The point is the electoral rules, system, process has been so corrupted it is too easy to cheat, and whether or not that actually happens, the majority of the electorate has serious concerns about the validity of the vote. We need rules, regs, systems, processes in place to ensure that only eligible registered citizens vote and they only vote once.
We have to have confidence in our electoral process and assurance that it is fair and honest for our constitutional republic to prevail.