It's pretty simple: there is a burgeoning Reactionary Left in the US. For the last few generations 'left' essentially meant 'progressive' so there's some lag in updating people's mental schema and naming it what it is. As a foreigner, I am less worried by its existence (it's not unique with regards to other countries, and it's relatively small) than by the willingness of the more mainstream left to either downplay or appease it... But the US also have a very opportunistic political culture, so they're probably used to foster some narrative (it reminds me of the Republicans in 2009 wondering how they can take advantage of this Tea Party thing. Same thing here, with the Dems trying to find a way to use these identitarians to their benefit -- what could possibly go wrong?).