There’s a deep-rooted discomfort at the heart of “BlacKkKlansman” and it’s the fact that instead of being a historical, true story poking cautionary fun at the ignorance of the past, it instead feels like a howl of furious irony at the recidivism of modern-day America.

In 1979, Ron Stallworth (John David Washington), Colorado Springs’ first African-American police officer successfully managed to…