The Democrats always take the high road or the decorum path every chance they get.
This theory that Dems don't play dirty is such a bald faced lie. Its rooted in the mythos of the party as an organization of high minded intellectuals and squishy naive good-natured hippies. But anyone who has gone through the trenches of a Dem primary or even bothered to recall the fine details of a general election, know this to be utterly false.
Dems are more than happy to smear their opponents as anti-American, even to the point of accusing them of outright treason. Liberal media orgs and influencers regularly advance personal attacks on their opponents' personal lives (Obama himself won his Illinois Senate seat on the back of the incumbent's infidelity), parade around "body language experts" and other hockey pseudo-scientists to degrade the reputation of the opposition, and outright fabricate claims (the Steele Dossier "pee tape" being the liberal companion to the conservatives' "Whitey Tape" from four years prior) for the entertainment of a gullible base.
The Democrats could have delayed ACB plbeing but on the supreme Court untill election time but they actively decided not to do so.
The Dems could have put a Senator at the head of the Judiciary Committee that wasn't drooling her way through the hearing. But Feinstein's cemented position as senior California Senator was the result of the exact kind of cut-throat politics that has entrenched horrifyingly corrupt and incompetent politicians from Henry Cueller to Joe Manchin.