the only logical answer is BLM is simply a racist movement, otherwise it would protest for the current slaves in africa and not attack figures of american colonisation and foundation.
BLM is a terrorist organization that is also a black supremacy group. They
only care about black people who have been killed by white people, even though these killings make up a smaller proportion of killings than populations of both would indicate.
I strongly suspect they are currently receiving foreign support, as their ability to spread propaganda has grown much too much, much too quickly. Even if they are not receiving foreign support, I believe something nefarious is going on.