Last response, then I'm out.
I assume you are referring to this 19th Century Lincoln statue in Boston, which has been considered controversial for decades:
The humbled black man kneeling before the Great White Father. I'm sure it seemed like a good idea at the time. Its time has passed. Take it down. As I said, it's just a symbol - but it's a symbol which no longer reflects our shared values.
Re the other two examples you cite, as far as I can tell that was just plain vandalism. Not the first time African-American statues have been vandalized and I am sure it won't be the last. I don't think anyone is seriously calling for their removal.