It's important to point out the context for why commentators (left and right) a made case for Franken not stepping down. Those on the left saw it as naive for the Dems to hold themselves accountable to a MUCH higher bar than than the Republicans hold themselves to (Trump and Moore).
Some also called for due process (meaning the women shouldn't automatically be believed) and for proportionality (essentially the Ari Fleischer argument).
However, Democrats ultimately decided to set aside the due process concern because it makes the issue much harder to exploit as a political weapon. It means not jumping to conclusions. It means taking denials as seriously as accusations. It means being ok with hostile questioning (essentially cross examination) of the accuser and pointing out possible holes and inconsistencies in her story. It means highlighting facts that might weaken her credibility. It means seriously entertaining the possibility that Roy Moore wasn't necessarily a child molester, which means Democrats don't pick up a Senate seat. It means not just assuming that Trump is lying when he denies his accusers. The potential benefit of summary condemnations was too great.