Both President Lincoln and Mr. Douglass used this phrase to describe the Democratic Party. It seems that this mobocratic spirit and/or mobocracy has been a cornerstone of the political left for quite some time.
From the pre-civil war seccession movement of the Democratic South, to the formation of the KKK, to bringing in the Mafia and their union compatriots (a stronger mob) to eliminate the KKK, to the socialist, anarchist and union mobocracy of today.
Today we're told that the mobocratic spirit is "what Democracy looks like". My response is hardly and that we thankfully live in a Constitutional Republic.
Here's a screen shot of the results when I Googled mobocracy.
I don't find it odd at all that the Wisconsin Union logo is front and center.