Quote: "Maybe if they spent more time DOING things and less time complaining about white people there would be more futurists/engineers/painters/doctors etc instead we have BlackLivesMatter doing die-in's in shopping malls or protesting the deaths of career criminals..."
Perhaps the original commenter is accidentally committing a subtle act of prejudice, but you are being overtly racist.
Noting that the original commenter may or may not be black, Your choice to attack black people is independent of your concern about the potential prejudice in the original comment.
At least this makes it clear where you stand; your comment was not about fighting prejudice.