A tense documentary that winds its way through online right-wing politics, Simon Klose’s “Hacking Hate” is a detailed (if occasionally disconnected) exposé of contemporary extremism. It follows Swedish journalist My Vingren as she embeds herself within white supremacist digital spaces. By chronicling her investigations, as well as her interviews with several experts on content moderation, the film introduces numerous parallel threads spanning the entire globe, from the U.S. to Scandinavia and beyond, though it doesn’t always manage to weave them together.

Vingren is a committed and knowledgeable subject, referred to by some as the real-life “Girl with the Dragon Tattoo.” Her proclivity for tracing online footprints comes in handy during “Hacking Hate,” when she not only creates numerous fake profiles to court invites from white nationalist groups, but finds a trail of digital breadcrumbs where most would not think to look. In the process, she gradually uncovers...