What I mean is that this teaching should instill in employees the confidence that it's totally ok and safe and even advised practice to say "f_ck off" to your manager if s/he makes unwanted personal advances and to report them to HR if they don't.
If the only way to deal with harassment is to report it to HR people will hesitate because it's severe, it's process, it involves other people (and HR is not your friend).
It is all the things that you might want to save the person that might honestly misread you because he's a dumbass.
Companies should kind of own up to the fact that their employees are not asexual and that some people make some misguided attempts to flirt with co-workers and some accept the flirt and reciprocate.
Female colleague from the story who thought she was blowing the situation out of proportion probably had way more liberal opinion of office mating games.
Instead of outright banning this they should just discourage it (because it breeds conflict) and create obvious way for employees to clearly opt-out from this office activity (because those that don't want to play are horrified by human mating rituals, myself included).
I think in old days simple slap in the face had this role (totally unacceptable today, today's men can grow up without being slapped even once so they wouldn't think it's an assault or some SM sh_t). Not sure though what were men doing 50 years ago to fend off female advances apart from wearing a ring and acting completely disinterested.
That said, what I'm getting at, is that there are times when people step over the line into harassment in full view of others.
Not just in sexual harassment either. Verbally or physically abusive behavior falls into this category as well. Sometimes the victim may be afraid or unwilling to stick up for themselves but ultimately harassment hurts the whole workplace so third party reporting can be an extremely valuable measure to address the issue.
It would save HR a lot of work and many young employees a lot of confusion and stress.