On the contrary, the offense against God by the heretic is so great and the danger to the Church of not doing so is so great, that we are called upon to do exactly that:
7. Finally, [by this Our Constitution, which is to remain valid in perpetuity, We] also [enact, determine, define and decree]:-
that any and all persons who would have been subject to those thus promoted or elevated if they had not previously deviated from the Faith, become heretics, incurred schism or provoked or committed any or all of these, be they members of anysoever of the following categories:
(i) the clergy, secular and religious;
(ii) the laity;
(iii) the Cardinals, even those who shall have taken part in the election of this very Pontiff previously deviating from the Faith or heretical or schismatical, or shall otherwise have consented and vouchsafed obedience to him and shall have venerated him;
(iv) Castellans, Prefects, Captains and Officials, even of Our Beloved City and of the entire Ecclesiastical State, even if they shall be obliged and beholden to those thus promoted or elevated by homage, oath or security;
shall be permitted at any time to withdraw with impunity from obedience and devotion to those thus promoted or elevated and to avoid them as warlocks, heathens, publicans, and heresiarchs (the same subject persons, nevertheless, remaining bound by the duty of fidelity and obedience to any future Bishops, Archbishops, Patriarchs, Primates, Cardinals and Roman Pontiff canonically entering).
To the greater confusion, moreover, of those thus promoted or elevated, if these shall have wished to prolong their government and authority, they shall be permitted to request the assistance of the secular arm against these same individuals thus promoted or elevated; nor shall those who withdraw on this account, in the aforementioned circumstances, from fidelity and obedience to those thus promoted and elevated, be subject, as are those who tear the tunic of the Lord, to the retribution of any censures or penalties.
Again, all this is true enough---but nowhere does any of this state that we as private individuals have the right to make the binding determination that a particular prelate is a heretic, as opposed to simply being in error; that is for the Church and the Church alone to determine.
"Law is not a mere contractual order of things, but a participation in the will of God or Divine Providence, and a breach of it therefore requires the intervention of the lawful custodian and guardian of the law...Only the legitimate authority, as the founder of law and the representative of the supreme Ruler, is entitled to demand justice and inflict the necessary penalties on transgressors" (Augustine, Vol. 8, p. 69)