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Yes, but so what? Even if any of the components of such an insult are true or truish, you have to know the person you're insulting to make them cut. If you don't know the person, they don't cut in the same way because they don't revolve around something so obvious, and therefore knowingly insultable, as superficial aspects of a person's relatively recent ancestry and heritage, which the racist insult implies are somehow bad or something to be ashamed of. Something non-obvious or untrue that you don't actually know of a person can always be denied or shrugged off, or, as in the present example, simply returned--'no, you're the wasteman'. The racist insult will still be there and unanswered.
An equivalent kind of insult to racist insults for the majority group, which in most contexts where racist insults are made, simply doesn't exist, as they are historically connected to victimisation of minority groups, making them doubly hurtful.
One can be pretty damn insulting without bringing race into it though.
"Mummy hating dog rapist" usually hits the nail on the head.