Obviously, what happened is that Horvath was already upset from the weirdness that had transpired thus far - and based on the article, it does sound pretty weird.
Because of this she read a lot of 'meaning' into the hula-hooping that just wasn't there. It's hard to see how this situation could be a last straw otherwise.
[1] i.e. "hula hooping in the office" is out of the ordinary ... watching something out of the ordinary is normal
A lot of "normal" interactions between men and women are fraught with creepy weirdness due to the way we're socialized. This is well studied, even if you find the conclusions of those researchers unpalatable.
There is a famous early cinema experiment which cuts the same closeup of a face with three different scenes (don't remember, I think a funeral, something to eat, whatever). Each time the viewer interprets a different emotion into the face (sad, or hungry, or yearning, or whatever).