Unlike Trixie here, the original dancer was portrayed at a slight tilt. Most people saw her rotating clockwise, because that would mean that we were seeing her from slightly above. Otherwise, we would have had to be viewing her from slightly below, a less intuitive presumption.
Also, most people are right-handed, so there is a slight unconscious bias in attention towards the right side of the body. This meant the dancer's stuck-out arm and leg were presumed to be on her right, which *also* meant she would have been spinning clockwise.
In Trixie's case, there is much less tilt than with the dancer, and I would expect most people to presume her stuck-out "arm" is her right, thus she would be spinning counter-clockwise for most people's views.