Two things:
1. "Are we really to think that a young man who ends up with a broken bone won't learn anything from that experience?"
If the situation was bad enough to break bones then presumably he also got charged? That would be part of the learning experience.
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2. " alcohol is a risk factor"
Exactly. How is a young girl to use the defense techniques if she is falling down drunk? Answer: she can't so teaching this stuff also means teaching them not to get so drunk they cannot take care of themselves.  My daughters know better than to get blackout drunk, or anywhere close to it, for all sorts of reasons of which sexual assault is only one.