"We already know why the perpetrator did it - because they wanted to have sex and thought they could get away with it."
Sometimes it is just trying to start up a relationship. A lot of what is labeled as harassment is only that because the "victim" didn't want it to come from that person, i.e. if someone she was attracted to did the very same thing it would be ok. Women in the office have said exactly that (but never when a man is in sight). 
The problem is that many women just wait for the men to make the first move so the poor guy has no real way of knowing in advance if his advance is welcome or not. And if it wasn't it gets labeled as "harassment" or worse.
My advice to guys is: stay away from women at work. It really isn't worth the risk.
Search on youtube for things like "Men not marrying? How deep does "the problem" go?",  "Men Flee Marriage", "Not Enough Men Left", "Women Are Upset They Can't Find a Man" etc.
Men are starting to wake up and abandoning marriage/commitment.