At very best, such a claim misses the crucial context of Black Lives Matter, which is not that ONLY Black Lives Matter, but quite the opposite: Black Lives Matter ALSO. In fact, though this argument has been become searingly heated with the awful murders of African-Americans in Louisiana and Minnesota and murder of police officers in Dallas last week, I've been seeing people point out this all-important "also" subtext on the Web and TV ever since the Black Lives Matter movement began in 2013, to finally address a problem that has been going on for centuries.
Why have so many people missed this obviously implied "also"? A better question would be why has anyone? As Marshall McLuhan pointed out back in the 1960s, everyone who communicates does so on two levels, a figure and a ground. When someone says some music is cool, people intuitively understand that you don't need to put on an extra shirt or an overcoat to enjoy it.
There is some minimal education needed to get the ground, the context, of any given statement. A child would not instantly know that cool music has nothing to do with literal temperature.
Bur how could any sentient human being alive the past decade or longer not immediately get the context of Black Lives Matter - not immediately understand that it's a plea for black lives having as much worth less as white lives, and, yes, as much worth as lives of police?
As much worth, not more worth, and the fact that Giuliani and others somehow miss this, and say that Black Lives Matter is racist, only demonstrates, once again, that they are the racists themselves.