One of the salient features of the modern left is the inability to tell when it is being serious. One of the Hated Instapundit's minions found this and no one is really sure if it is a parody.
The reason for the confusion is that the left has become explicitly anti-white. The old goal of a colorblind society and racial integration has been replaced by naked appeals to racial grievance and solidarity. "Whiteness" is the Great Satan that all right-thinking people need to oppose, though what will replace it is entirely unclear.
The irony is that the old instruments of white supremacy have all but disappeared. The KKK is almost gone, and a good many of its remaining members are likely paid informants. Mark Steyn's run-in with the hate speech commissars in Canada demonstrated that a good deal of the racist posts on Stormfront were made by police or investigators.
However, in imagining white nationalism, the left is now creating it. No ethnic group likes being told it needs to drop dead or is the root of all evil.
There was a time within living memory when groups now lumped together as "white" didn't like each other very much. WASPs had few good things to say about the krauts, frogs, micks, spics, dagos, polacks and even the limeys were looked down on as effeminate. The avatar of this belief was the fictional Archie Bunker, who waged weekly war on his dim-witted daughter and idiot son-and-law.
In 1970, there might be some consternation about an Italian marring into and Anglo-Saxon family, and gaining a Polish branch was fraught with jokes regarding the alleged stupidity of that tragic people.
Now, they're all tarred with the same brush. They all carry the same bland label of "white."
One of the salient features of the left is its ignorance of history. They love to invoke Hitler analogies, but they are always wrong, often hilariously so.
The Irish people suffered greatly under their English overlords and maintained their faith and language against far worse sanctions than tweets and social-media shunning. The notion that millions of people would roll over and submit to extermination without any resistance other than name-calling could only originate among clueless millennials and their clueless media standard-bearers.
The left likes to talk about how diversity brings strength, and in a sense it does: All those put-upon Poles, Italians, Irish, Germans, French and Spanish now have something to unite themselves with the patriotic remnant of the Anglo-Saxon ruling class.
The left is poking the tiger. It won't like what it gets if the beast actually rouses itself and strikes back.