Shortly after the election, there was a dispute on the left as to whether “alt-right” was an acceptable term. Many rightly viewed it as a euphemism meant to obscure white-supremacist, Nazi-sympathizing beliefs and concluded that those who used the term were complicit with the deplorables’ attempt to “rebrand.” I was among those who believed that the term was analytically helpful, especially because the rhetorical effect of the euphemism could be defused simply by associating “alt-right” with racism, Nazism, etc., at every turn. Calling them neo-Nazis is accurate in a literal sense, but they are clearly not “Neo-Nazi skinheads,” which is the popular sense of that term.
In other words, I believe the term alt-right is potentially helpful in capturing what is distinctive about the contemporary articulation of extreme right-wing racist ideology. In general, I think we need to get better at recognizing that there is no “racism in general” — in every historical moment, the social and political tools clustered around the concept of race are rearticulated in new and often unpredictable ways. As this article on online radicalization of young white men shows, a lot of what we are seeing today in alt-right circles is surprising in light of the conventional wisdom that racism is some kind of outdated holdover that will soon die out. In many ways, they are ahead of the curve in terms of things like meme culture, translating online engagement into real-world action, etc., not to mention that they have managed to ditch the leather clothing and find their way to a J. Crew (always a big focus for the media for some reason).
And this brings me to the Benjamin allusion in the title — though we see it less and less, there are still a lot of people who think you can read off the appropriate level of social justice by looking at the calendar. But once we recognize the distinctiveness of the alt-right, we can see that racism isn’t some random leftover of a bygone era, but a phenomenon that is incorporated into our present social order and political moment. It is not the return of the repressed, it is the exacerbation of something in the present. In other words, the violence at Charlottsville did not happen despite the fact that it’s 2017, but precisely because it is 2017 and not some other historical moment. We can’t just wait for white supremacy to die off through demographic attrition. It’s not solely a struggle against the dead weight of an older, less enlightened generation or the inertia of institutional structures, though it is also that. This is our problem, right now.
An und für sich 
I think you’re exactly right to emphasize the properly present moment of what has emerged with the “alt-right” movement. All of the novelty involved with the construction of this form of reactive subjectivity can be overlooked if we think that it’s merely the resurgence of some prior images of being. Every day we’re creating and recreating the conditions for who we announce ourselves to be today and who populations will end up being tomorrow. Understanding the forces at play (such as presented in the article posted about online radicalization), but also these sub-cultures on reddit and 4chan and Facebook groups, the communities of thought created by the propogation of alt-news outlets (e.g. breitbart and zerohedge), allows us to more proactively address it. An extremely fascinating article was shared with me earlier today describing Steve Bannons political ascent via the very historically novel circumstances of the video-game community and observing the peculiar dynamics of online communities, he learned there and later through his observance of what I believe was called “gamer-gate” the power hidden with the mobilization of online communities. This ultimately has consequences that are still unknown to us about the interplay of anonymous and virtual subjectivity with concrete real world (embodied) issues. We won’t fully grasp it all until we treat the present as present.
I saw an impressive example on Twitter of the kind of euphemism policing you describe re the alt right, where someone was saying “neo-nazi” was a deplorable euphemism, obfuscating the fact that these people are actual Nazis. Apparently fascism can only be recognised as fascism if it is located in the historical time of WWII.