As a director, Raoul Peck is a passionate and protean talent. He has been making films for close to 30 years, and he’s right in the middle of his most seismic moment with “I Am Not Your Negro,” his searching meditation on James Baldwin, which has struck a deeper, wider chord than anyone might have anticipated. In 2000, Peck made a galvanizing drama about Patrice Lumumba, the first democratically elected leader of the Congo, that was the cinema’s most perceptive (and agonizing) study of colonialism: what it is, how it works, why its legacy is so hard to shake off.

Now, at the Berlin Film Festival, Peck takes a different leap altogether with “The Young Karl Marx,” a classically conceived and executed biopic that traces how Marx, as a struggling family-man writer in the 1840s, came to create “The Communist Manifesto.” It’s an impeccably crafted and honorable movie — but, I have to say, not a very enthralling one. If you didn’t know Raoul Peck’s name was on it, “The Young Karl Marx” would look like a so-so Merchant Ivory film from 1993. It’s dutiful, but it’s also superficial and polite, and it commits the genteel sin of the old biopics: It turns its hero into a plaster saint.

Is Karl Marx morally responsible for everything in the 20th century that happened in his name? Of course not. Yet if you look at that legacy — mass incarceration and death (in China, the Soviet Union, Cambodia) on a scale comparable, in some cases, to genocide — then you can at least ask the question: Was the madness of 20th-century Communism encoded in the naïveté of Marx’s writings? In “The Young Karl Marx,” he’s played, by the German actor August Diehl, as an eager, bushy-haired (and bushy-tailed) liberal philosopher, fighting for the proletariat even though he’s never been a working man himself.

An opening title provides the context for Marx’s struggle: The Industrial Revolution has arrived, and the old order that ruled Europe — the monarchy, the imperial aristocracy — is getting ready to topple. (It would have happened anyway; Marx gave it a nudge.) In the early scenes, when we meet Karl, all glorified schoolboy fire, and also Friedrich Engels (Stefan Konarske), the very bourgeois factory owner’s son — he wears a top hat and high collar — who becomes his comrade and writing partner, the movie makes the point that the whole scheme of analysis we think of as “Marxist” was already in place. The perception of the class system, the rage against the capitalist oppressors, the dream of a world in which workers would unite as brothers: Karl Marx didn’t invent any of that.

So what did he do? In “The Young Karl Marx,” he gets into friendly debates with Pierre Proudhon (Olivier Gourmet), the firebrand French anarchist who preaches against the world of assembly-line labor (what he calls “the new machines from hell”), and he speaks, rather defensively, about how he doesn’t want to be “a scribbler urging world revolution.” (Good luck.) Then he meets Engels: The two take the piss out of each other for about five minutes, but after that it’s all high-minded bromance. “You’re the greatest materialist thinker of our times,” says Friedrich. “A genius.” That’s quite a claim, but the film never begins to explain what it means. As presented, Karl’s big insight appears to be that the dissolution of the class system can’t reject materialism — it has to be about the redistribution of it. Yet the movie, oddly, never makes us feel the radicalism of this idea; Karl just presents it as common sense.

August Diehl is a skillful actor, known for his work in films like “Inglourious Basterds,” but he and Konarske are both a little too fetching and caught in their own placid glamour to play these upstart philosophers with the right tone of prickly fanaticism. In “The Young Karl Marx,” they’re like a couple of indie rock stars, grooving on each other’s riffs. Engels, to write his book about the struggle of the worker, has done his research, mostly by romancing the cutest worker (Hannah Steele) in his father’s textile mill. As the two men skip around the continent, going from Germany to Paris to London, nattering on in drawing rooms about the proletariat as if they were collaborating on the world’s most ardent term paper, the one dramatic constant is Marx’s struggle to take care of his family: his radiant and endlessly supportive wife, Jenny (Vicky Krieps), and young daughter. He does a good job of it, and Diehl, in fact, makes Karl so centered and loving that he’s never thrown off balance. I kept wishing for him to have a moodier side — wondering what, say, an actor like Oscar Isaac might have brought to the role. The Karl we see in “The Young Karl Marx” is never more (or less) than the sum of his compassion.

Peck stages the movie with the kind of stodgy middlebrow competence that, after a while, can wear you down; he doesn’t make glaring mistakes, but he never upsets the apple cart. And maybe that’s because he’s lost, in his way, in a view of Marx that’s too automatically romantic. The film is at its best when Karl gets concrete about what his philosophy means — like his crusade against child labor. Yet it buys too easily into Marx’s utopian (and deeply bourgeois) view that the class system is a conceit imposed by the oppressor, and that the attempt to try and equalize everything is simply the higher wisdom.

Near the end, there’s a classic corny biopic moment when Marx and Engels are writing “The Communist Manifesto,” sculpting the sentence that reads “A spectre is haunting Europe — the spectre of Communism…” The weight of the words never feels spontaneous; it comes with a Great Books seal of approval. But then, startlingly, the closing credits play over clips of news footage from the 20th century, with Bob Dylan’s “Like a Rolling Stone” blasting on the soundtrack. That’s certainly the kind of audacity this safe and slightly dull movie could have used more of. Yet if Peck is saying that Marxism is having a moment of comeback, the 20th century (unlike the 19th) isn’t a great advertisement for it. I watched those clips thinking: What would the young Karl Marx have made of what was done in his name?