It sounds like the professor made it clear she was speaking in terms of population averages. So unless you can find empirical evidence that those statistics don't apply to that slice of the population, then there's absolutely no problem with what she said. She didn't say "15 of the men in this class are rapists."

Law students aren't learning to be statisticians, epidemiologists, or policy wonks. Emotionally moving people to act upon a collection of documented facts— be it in trial or a contract negotiation— requires persuasive speaking and strategy. She made the breadth and consequences of rape palpable to her students not only by giving it a face, but giving it their faces. Since this poster, years later, immediately recalled that story when prompted, I reckon it was thoroughly compelling.