I certainly agree that it's disappointing that people will so readily believe false and humiliating stories about somebody they don't like.

But describing it as "a new low" against the background of a violent disruption of Congress, with the intent of interfering with the peaceful transition of power... that's not a phrase I'd have thought to use. The mockery is disgusting and disappointing, as is the gullibility of its spread, but both are very common. The violence, by contrast, is genuinely novel.