That incident happened after a company event, isn't that considered private time? I mean, she would have had to agree to go with the co-worker, during their off-hours, in the first place and he might have interpreted her willingness to go along as a signal of mutual interest (romantic, sexual) in each other?

That isn't meant as an excuse for such creepy, if not straight up criminal, behavior. But as somebody with some social issues of his own, I can relate quite a bit with not being able to properly interpret social and body cues.

To me, the vast majority of people are walking blackboxes where I have no clue how they would react to most actions of my own. Which boils down to me acting rather passively in most social situations out of fear I might break some unspoken rule, misinterpret the current mood in the room/between people.