It's not a lie; it's a myth. All countries have them, because the past cannot be changed. If America has not always been striving to get better, then it cannot now claim to be striving to get better. We MUST regard our past as a struggle to improve, a struggle that continues. Any other view is too dispiriting to inspire us to push on.
Prof. Glaude is specific about our faults, vague about solutions. There is no new beginning. A country is no more able than a person to make a good first impression the second time around. Black people will make their own bootstraps and then pull themselves up by them. They deserve better, but they will not get it. They can deal with that reality or not.
In the real world, the most achievable solutions are the ones that are least disruptive. Black people need to TAME racism, not "dismantle" it. The most effective (not fairest, but most effective) strategy for Black Americans is to remove the obstacles to making bootstraps. Much progress has been made in that direction, maybe even enough. Is there an academically successful Black high school student who cannot get into a good college and find a way to pay for it? Anger and justice are trumping wisdom and progress.