"For example the homicide rate in Japan is much lower than in Jamaica; from this it follows that Jamaicans are on average more homicidal than Japanese. That's a negative generalisation. It's also true."

To me, a generalization is where you infer that because a general fact exists (e.g. the homicide rate) there is consequently a more specific fact about each member of a group. I feel like you have stopped short of actually making a generalization, or are leaving it ambiguous as to whether you have made one. If the homicide rate implies something about each Jamaican, what does it imply? I find the equivocation over such matters more viscerally irritating than the racism itself.