An important, hot-button topic gets an amusing, convincing if cursory treatment in “Can We Take a Joke?”, a documentary about the war on free speech in America.

It’s not a film about government censorship or old-school State Sponsored Religion restrictions on what people can say or write. It’s about the political correctness that has so infected college campuses and the Internet that stand-up comedians are spending a lot of time apologizing, when they should be trying out new jokes that prick the orthodoxy and challenge sensibilities.

Insult comics from Lisa Lampenelli to Gilbert Gottfried marvel at how emboldened hecklers have become, at how colleges — supposed bastions of airing challenging ideas and hearing others out — have become the home to the “mob censorship” movement.

Director Ted Balaker begins with a parade of public apologies, from Don Imus and Jimmy Kimmel and others, for jokes they’ve made. It shows us video of coed fascists, shouting down plays they take umbrage to, charging the stage to snatch the microphone from comics who offend them.

And scholars, comics and others weigh in on the public’s runaway “right to be offended,” stunned that a generation has grown up to “become what they hated” — censors.

Penn Gillette and Gottfried and a Lenny Bruce biographer marvel over the legendary martyr for free speech who must be rolling in his grave over battles he fought with the anti-free speech conservatives of his day made moot by anti-free speech liberals.

Bruce, whose challenging work of the 1960s is generously sampled here, pushed boundaries that George Carlin and Richard Pryor exploited after him, and generations of comics have enjoyed great freedom in the decades since.

As anybody who has spent 15 minutes studying stand-up could tell you, NOTHING should be off-limits. Or is supposed to be. Gottfried famously told the first post 9/11 joke about 9/11, and was more far famously fired from a duck-quacking insurance spokesman gig for making Japanese earthquake/tsunami/meltdown cracks “too soon” after that tragedy. Thanks to a “Let’s get him FIRED” Internet campaign.

The movie wanders off topic, sidetracked by Internet shaming and its consequences. Considering how brief “Take a Joke” is, that deflates the message and feels like filler.

After all, everybody from Jerry Seinfeld on down the comic hierarchy has complained about this campus-fueled assault on free speech. More voices would have been nice, and just one person, on camera, defending the whole tyranny of “safe space” where “hate speech” and “bullying” is banned on campuses is a grievous omission.

Hearing from the “other side” in a movie that advocates advancing knowledge and understanding through free speech seems like, um, a no brainer.

MPAA Rating: unrated, profanity

Cast: Gilbert Gottfried, Lisa Lampenelli, Karith Foster, Penn Jillette,
Credits: Written and directed by Ted Balaker. A Samuel Goldwyn release.

Running time: 1:19