It was strictly forbidden by state law.
The case, after the election, went all the way to the state Supreme Court, which had a 4-3 Conservative/Leftist split. One of the "Conservatives" Justice Brian Hagedorn, sided with the three leftists in saying they could not throw out the ballots after the election, because it would be too disruptive.
"Striking these votes now — after the election, and in only two of Wisconsin's 72 counties when the disputed practices were followed by hundreds of thousands of absentee voters statewide — would be an extraordinary step for this court to take. We will not do so."
This followed the situation seen nationwide. Before the election, lawsuits favoring Trump were said to be "too early". After the election, lawsuits were said to be "too late".
The Republican lawsuits were never "just right".
“Goldilocks lawsuits”
Same for lawsuits over Obama’s eligibility. Apparently when the shadow government decides that an issue is not for the judiciary to consider, they are able to get every single black robe in the country to fall in line and cower before their decision.
If that’s not the case, then it’s certainly how it appears to an outside observer.