Why don't you test your theory by walking up to some people and calling them slurs. See if they all shrug it off because at least you're not a cop shooting them.
That would fall outside the bounds of words on a screen, written indiscriminately.
It was a claim about hate speech and not "words on a screen." But you could try texting people you know if you think that dimension is important.
Sure you just need to dress up as a cop and shoot them for the control group.
Except when the people hurling racial abuse are just winding themselves up to committing a murder[1].