The interesting thing is how they're succeeding. We haven't exactly seen a resurgence of the Klan of late, you might notice.
What's happening instead is that anything that can even be vaguely construed as racist, even if it doesn't hold up under scrutiny -- especially then -- becomes the subject of mob focus and attack.
Because if you can convince the mob to "righteously" attack innocent targets then you get fireworks. The mob is told that they're on the side of the angels and the target is a despicable fascist who should burn in hell, so they cross every line to take out the intolerable evil. Then it turns out the target wasn't, in actual fact, the literal devil, and that gets other people hopping mad at the mob over the real perils of mob justice. But by that point the mob has moved on to the next target who we're again assured is a very bad person, this time for real, promise.
It's tempting to go too far with this and come up with some kind of conspiracy theory where BLM as a whole is nothing but a Russian plot, but there are far too many real people in it for that.
What seems more likely is that you have an existing movement with many well-intentioned people but no strong leaders, and all it takes is an adversarial propaganda effort to whip enough of them into a frenzy and point them at a false target that will purposely generate a backlash.
Then you've got two huge camps of honest people fighting each other over a manufactured conflict which isn't even at the root of their genuine concerns.