Scott Renshaw’s review published on Letterboxd:
As per more or less usual for a Spike Lee movie, BlacKkKlansman is about at least a dozen different things at once. But the one that stuck with me is one I haven't seen discussed all that much (although it's certainly possible I've missed it). In short, this feels primarily like a story about the role of media messages in shaping the public discourse on race. It's a tale of the Overton window dressed up as a buddy-cop movie.
That feels evident from the outset, as an iconic scene from Gone With the Wind gives way to Alec Baldwin's racist speech, where he repeatedly stops, pauses, clears his throat, does another take. If a movie does indeed teach you how to watch it from the beginning, Lee is teaching us that this is a movie less about the philosophy of white supremacy than about its delivery--how racism is presented to the public in a way that connects. That's certainly most evident in the discussion of how David Duke is trying to put the face of the KKK in a three-piece suit rather than a robe and hood, and in the way we hear his recorded messages not as rabid screaming but as a guy whose voice tries to tell you, "Doesn't this all sound perfectly reasonable?"
But that idea is also crucial to the magnificent sequence juxtaposing the Klan viewing of Birth of a Nation with the Belafonte character talking about a direct consequence of its existence. A repugnant idea "written with lightning" is still a repugnant idea, and a savvy artist can deliver it with enough impact to change behavior.
There are several other points at which BlacKkKlansman circles back to this idea of how the things people see in the media shape what they think is acceptable, from the conversation between Ron and Patrice about the relative merits of Shaft and Superfly, and a comment about the way Archie Bunker made the idea of a "bigot" unpalatable enough to move the window in the other direction. Then it all comes home in the epilogue of the 2017 Charlottesville events, and Trump's subsequent response. This is how hatred begins to win: When the President of the United States of America delivers a message about "very fine people" that moves the window back again, just like a movie lionizing the Ku Klux Klan renews its vitality.