Down to interpretation. She is clearly gesturing at Celia Ward and continues to do so just as the cyclist comes into shot. This wasn't some young tearaway cycling at break neck speed on the path. Auriol Grey could easily have stepped further to her right but she held her ground and continued to gesture. It's that combination which I think most people will see as 'forcing' the cyclist to try and take evasive action which saw the bike go off the kerb with tragic consequences.Looking at the video, I don't think the pedestrian forced the cyclist to fall into the path of traffic. A cyclist in control of their bike should have been able to stop. And I don't think they should have known their actions would be likely to kill anyone.
I'm guessing that the following accident was horrific, and that the pedestrian's actions from then on are a large part of the reason they were found guilty.