The “alt-left” label is simply meant as a slur, a way to associate America’s most consistent foes of oppression and exploitation with those who mean to shred whatever social and civil rights we still have. But it does connote a real style and temperament – a willingness to speak to an anti-establishment mood, to break with “politics as usual” in a far more fundamental way than Trump did.
Of course, in a time of rising authoritarianism, it’s understandable that liberal commentators would be wary of certain forms of anti-establishment populism. The collapse of an unjust order doesn’t mean that something better will take its place. But the political figures often brought up in conjunction with the “alt-left” are far from vengeful internet trolls.
Bernie Sanders, Jeremy Corbyn, and Jean-Luc Mélenchon all have wide bases, built through campaigns around a social-democratic program in favor of worker protections, a social safety net, and more popular engagement in the decisions that affect ordinary people’s lives. That’s not extreme politics; it isn’t demagogic politics. It’s politics that can win over tens of millions who feel like politics hasn’t been working for them and might otherwise be won over to the populist right.