They need a reality check.
Physical strength. Size. Muscle mass. All the things that put a healthy male far more at an advantage to any given female, even if she is taller and heavier.
The bit where if they get punched full strength by a girl their size and weight, it'll probably hurt, but if they did it, she'd be out cold if not needing reconstructive surgery.
To not tell them this does a disservice to both, as at present, they may think 'oh, she's fine, she doesn't need any help, she's as big as he is' when a woman is in danger. Or not comprehend why an intoxicated girl needs more help.
Effectively, you have to tell him that he's at a massive physical advantage to pretty much every woman he ever meets, sets eyes on or hears of online.
And yes, he also needs to know that rape is a weapon of war.