Because after 5 seconds of research I had found something which shocked me enough to post it here!
Of course imgur is not representative, so I had a quick look for you at other places where gifs/short clips can make it to a sort of front page which is the same for the whole community (unlike instagram for example, where your discoveries are based on your previous likes). 9gag and reddit both have more than 50% female juggling clips, the other half is made up out of clips with men or clips with animals (juggling otters, stick spinning cats). In at least half of the male juggling clips it doesn’t seem to be about the trick or skill either, most of them are featured because something else happens, such as a fire juggler setting his friend on fire by accident, or Lauge getting hit in the face by his own club.
This remains a not very serious, thorough or representative research, which was never the intention!