Interesting read. I tend to agree particularly with the notion that the idea of being radical is contextual, it's not a fixed set of strictures or specific ideological prescription. Radical thinking is to expand the imagination beyond ideas we've already tried before.
For that reason I would say that at this point in time, Marx is not really radical thought. Much of what he prescribed, as its been attempted, has become more obviously a limited product of his time, in which he himself and his perspective were trapped. It has irreconcilable flaws that always curve it towards authoritarianism.
Rejecting the inclination to be precious about Marx and communism or any historical philosophy is probably the radical direction for our time, that's what leaves you in new territory looking for new solutions based on what actually works. Marx's ideas, like the guillotine, have failed broadly when implemented because while they're radical for their time they're still part of a less evolved social structure.
Now that the Soviet Union has been defunct for almost 30 years—and owing to the difficulty of receiving firsthand perspectives from the exploited Chinese working class—many people in North America experience authoritarian socialism as an entirely abstract concept, as distant from their lived experience as mass executions by guillotine. Desiring not only revenge but also a deus ex machina to rescue them from both the nightmare of capitalism and the responsibility to create an alternative to it themselves, they imagine the authoritarian state as a champion that could fight on their behalf. Recall what George Orwell said of the comfortable British Stalinist writers of the 1930s in his essay “Inside the Whale”
This is something that really makes discussions on the left difficult, people's unwillingness to admit that the Soviet Union and CCP weren't just "unlucky" attempts, but rather speak to a deeper link to authoritarianism and the right-wing that's built into Marxist ideas (intentionally or otherwise).
It's a similar feeling to when people talk about the founders in the US revolution as if they were strongly democratic. In reality the revolutionary elites would be considered anti-democratic by our modern understanding. Their thinking was still constricted and heavily classist and is actually responsible for a lot of the problems our democracy still struggles with to this day.
I only care about what the founders thought about democracy in terms of it being a contrast or waypoint. I believe modern ideas about what democracy should be are far superior, and I would never want to go back and apply the Founders' prescriptions. We need to move past them, and likewise I think the left needs to move beyond Marxism towards newer, more expansive ideas around human liberty and social relationships. Preferably ones that don't necessitate purges.
Marxism to me, for all practical intents, is a right-wing/conservative framework. Being to the "left" is about being able to philosophically adapt to new information. It's about not just incorporating that new info but also being able to drop ideas that don't fit reality. It's not a commitment to any specific recipe, rather, like the author says, it's about finding the most effective way of moving the needle towards the social relationship that we all want, where people are free and valued and don't need to compete against eachother just to live and thrive.