You subscribe to certain ideas that when someone makes a ststement your assumption is that it was to harm.
The fact a black character died its part of a larger conspiracy that black characters all die. So any instant, doesn't matter if its purposeful or not you make the connection to that conspiracy.
The director chose the people of colour characters that he did reinfore the idea of mutants are the oppressed. That the people that are overlooked and abused isn't gonna suddenly look more white cause its a CBM.
See how the kids killed the Reaver at the end and look at the complexion of those kids.