Fr. Guéranger says otherwise.
That's false and not what Gueranger says. In all of the orations, the kneeling/genuflection is directed to God. We're not kneeling to adore the heretics, schismatics, infidels, etc. that are prayed for in any of the orations either. That's not to diminish the reasons cited by Fr. Gueranger for not genuflecting during the prayer for the Jews (recalling the mocking genuflections to which they at least indirectly subjected Our Lord). While it was reported that the Roman soldiers performed the action, the situation was set up by the false Jew charges that Christ had declared himself a King (in opposition to Caesar) as a way to browbeat Pilate into condemning Him to the cross.
Trento was partially correct, partially because Hank Igitur never stated that the genuflection was TO the Jews, but FOR the Jews.