…Personally I think it is perfectly acceptable to respectfully criticize matters of discipline, which are not infallible…
The Jansenists were condemned for, among other things, criticizing matters of discipline. Why? Because ecclesiastial discipline is indeed infallible, but in a indirect and negative sense.
Pius VI condemned the Jansenist proposition that approved ecclsiastical discipline could be “harmful” or “dangerus” or “useless” or “burdensome” to the failful. (
Auctorem Fidei, 78) Thus, ecclesiastical discipline is protected in an indirect sense, from these characteristics. Which mean that although disciplinary norms are not immutable, and can be provisional according to the changing circumstances of the world, they are infallible in another sense.
Furthermore, according to Pope Gregory XVI,
Mirari Vos, 9 (1832):
“the discipline sanctioned by the Church must never be rejected or branded as contrary to certain principles of the natural law. It must never be called crippled, or imperfect"
So, it appears that Catholics are not completely free to criticize the disciplinary norms approved by the Church in any manner whatsoever. To do so would be contrary to traditional Catholicism.
Consider also…
Pope Gregory XVI,
Quo Graviora, 4-5 (1833), who adomishes those who criticize ecclesiastical discipline in such a manner which…
"… categorically that there are many things in the discipline of the Church… [which] are harmful for the growth and prosperity of the Catholic religion… these men were shamefully straying in their thoughts, they proposed to fall upon the errors condemned by the Church in proposition 78 of the constitution Auctorem fidei (published by Our predecessor, Pius VI on August 28, 1794)… do they not try to make the Church human by taking away from the infallible and divine authority, by which divine will it is governed? And does it not produce the same effect to think that the present discipline of the Church rests on failures, obscurities, and other inconveniences of this kind?
And to feign that this discipline contains many things which are not useless but which are against the safety of the Catholic religion? Why is it that private individuals appropriate for themselves the right which is proper only for the pope?"
According to Pope Pius XII,
Mystici Corporis, 66 (1943):
“Certainly the loving Mother is spotless in the Sacraments, by which she gives birth to and nourishes her children; in the faith which she has always preserved inviolate; in her sacred laws imposed on all; in the evangelical counsels which she recommends.”
And, according to two Catholic theological texts written during the papacy of Pope St. Pius X…
1909 Catholic Encyclopedia - “Ecclesiastical Discipline”…
“[Disciplinary Infallibility] has, however, found a place in all recent treatises on the Church. The authors of these treatises decide unanimously in favour of a negative and indirect rather than a positive and direct infallibility, inasmuch as in her general discipline, i.e. the common laws imposed on all the faithful, the Church can prescribe nothing that would be contrary to the natural or the Divine law, nor prohibit anything that the natural or the Divine law would exact. If well understood this thesis is undeniable; it amounts to saying that the Church does not and cannot impose practical directions contradictory of her own teaching.”
From a 1908 source of Catholic doctrine, P. Hermann,
Institutiones Theologiae Dogmaticae (4th ed., Rome: Della Pace, 1908), vol. 1, p. 258:
“The Church is infallible in her general discipline. By the term general discipline is understood the laws and practices which belong to the external ordering of the whole Church. Such things would be those which concern either external worship, such as liturgy and rubrics, or the administration of the sacraments. . . .“If she [the Church] were able to prescribe or command or tolerate in her discipline something against faith and morals, or something which tended to the detriment of the Church or to the harm of the faithful, she would turn away from her divine mission, which would be impossible.”
Consequently, when people make the blanket claim that ecclesiastical discipline is not infallible and can therefore be criticized at will, I question what they mean precisely. It is certainly not infallible in the immutable sense that positive dogmatic definitions are, but there is a sense in which ecclesial discipline is protected from being dangerous and harmful to the faithul, and to criticize discipline as though it were, contrary to the condemnation of Pius VI and other popes is far from traditional.