Prudence is not mere opinion but the “mother of all virtues”.
So it is that whilst it qualifies immediately the intellect and not the will, it is nevertheless rightly styled a moral virtue.
This is because the moral agent finds in it, if not the eliciting, at any rate the directive principle of virtuous actions. According to St. Thomas (II-II:47:8) it is its function to do three things: to take counsel, i.e. to cast about for the means suited in the particular case under consideration to reach the end of any one moral virtue; to judge soundly of the fitness of the means suggested; and, finally, to command their employment. If these are to be done well they necessarily exclude remissness and lack of concern; they demand the use of such diligence and care that the resultant act can be described as prudent, in spite of whatever speculative error may have been at the bottom of the process. Readiness in finding out and ability in adapting means to an end does not always imply prudence. If the end happens to be a vicious one, a certain adroitness or sagacity may be exhibited in its pursuit. This, however, according to St. Thomas, will only deserve to be called false prudence and is identical with that referred to in Rom., viii, 6, "the wisdom of the flesh is death"
People who’ve done their due diligence and humbly recognise their limitations to be truly prudent, will defer to the moral authority of the Church to guide and command. To reject a teaching of the Church which is unanimously accepted by the college of Bishops, is ‘false prudence’ and pretty grave especially when the agenda is to lead others to reject Church teaching.