Should Catholics be concerned about women rabbis in the same way that they are concerned about women priests?
Rabbis are not the Jewish equivalent of Catholic priests. A rabbi mainly is a teacher, although some rabbis are also judges of Jewish law. Although Judaism uses the term ordination for the ceremony in which such responsibilities are conferred upon a person, it is not a sacramental ordination in the manner that the Church understands ordination.
The distinction between women priests and women rabbis is an important one. The Church is concerned about non-Catholic Christian women priests because such claims that women can be Christian priests undermine the Church’s understanding of the Christian priesthood. The Church understands the Christian priest to be an alter Christus (“another Christ”) who acts in persona Christi (“in the person of Christ”). Because Jesus Christ was a man, those persons who act in persona Christi and are an alter Christus must be men as Christ is a man. Also, the Church is bound to Christ’s own example of choosing only men for this role.
This theology does not appear to apply to women rabbis. Rabbis are somewhat equivalent to catechists and canon lawyers. Although rabbis do lead Jewish worship services, in Judaism this is a function that can be done by an educated Jewish layperson. For these reasons, I doubt the Church have the same concern about women rabbis as it does about women priests.