It was the Romans, not the Jєωs, who mocked Our Lord with genuflections.
During which particular moment of Our Lord's passion? Didn't St. John say that the Gospels were *not* a full record of Our Lord's sayings and actions? What if there were some other event, perhaps part of Tradition rather than Scripture?
Were the Jєωs content to stay at home while Jesus was taken to Herod's Court and mocked there? Or did some of them tag along? When Jesus was condemned to death by the kangaroo court of the Sanhedrin, when they immediately began to strike him (Scripture says they mocked him and said "prophesy, who is it that struck thee?"), did some Jєωs perhaps throw in a few mock genuflections?
Or, during countless minutes along the Via Dolorosa on the way to Calvary, did some Jєωs mock genuflect as the King passed by?
Too many unanswered questions.
Long story short, I'm taking the Church's word for it, that the Jews mocked Our Lord with genuflections on this day, and so we shouldn't genuflect during the prayer for them on Good Friday.