The problem for the left is that they are kinda in a damned if they do, damned if they don't situation. The ideal method of handling political scandal is to ignore it. If you acknowledge it, you make people think about its possibility. A denial is still an acknowledgment of the claim.
So if they try to refute the information, they make more people believe it.
If they ignore the information, it will quickly disseminate on its own.
If they try to suppress the information, the Streisand effect kicks in.
They have tried all three so far, and each time it's just backfired and increased the number of people who think fraud had a major impact on the election. It's why they are going so hard after the audits directly because trying to win it in the court of public opinion is a loss no matter what they do.