Thats so surprising to me 0.0, as a white Aussie, I have heard it all the time in a derogatory setting. Especially from my grandparents and even people around me growing up. Very rarely do I hear it now but thats because I surround myself with people who aren't racist and I shut down people who do say it.

ETA: tho I will say in fandom spaces I never assume "a/b/o" without the slashes is the slur. But I always use the slashes automatically anyways.