CathInfo.com

“The word ‘manifest’ means, ‘clear or obvious to the eye or mind’. If not only the matter of heresy is clearly manifest, but the conscious and wilful profession of ‘a doctrine that immediately, directly, and contradictorily opposes the truths revealed by God and authentically set forth as such by the Church,’ is patently obvious to the mind, then the person who professes it may be judged by others to be a heretic, even without a juridical pronouncement of the Church, since no one needs any official declaration to be made in order to form a judgment of opinion on a matter that by its very nature is already ‘clear or obvious to the eye or mind’. The proposition that one is not a manifest heretic until an ecclesiastical judge pronounces that one is a manifest heretic is absurd on its face, since by the very fact that the heresy is manifest, it is already ‘clear or obvious to the eye or mind’ before any judgment is pronounced; yet this is precisely the silliness that John Salza and Robert Siscoe maintain in their rabid legalism. However, it is clearly the doctrine of the Catholic faith that if a person is a manifest heretic, then it is manifest that heresy has suapte natura severed that one from the body of the Church, and if he is a holder of ecclesiastical office, he has ipso jure automatically lost office and all habitual or ordinary jurisdiction ex natura hæresis, before any sentence is pronounced by the Church. Since the loss of office for public defection from the faith was prescribed in the 1917 Code to take place ipso facto and ‘without any declaration’, and it remains that way in the 1983 Code; it is absurd for anyone to claim that the faithful must wait for a declaration from Church authorities before judging in conscience on an ipso jure loss of office that takes place ‘without any declaration’; and that until a judgment be pronounced by competent authority, they need to and must remain subject to a heretic pope and to a vast portion of the hierarchy who have visibly expelled themselves from the body of the Church; while those pastors who remain faithful, and who are competent to judge, are either too blind or too frightened to speak.”

You don't know what you are writing about.  Leaving aside latae sententiae excommunication for heresy, only the Church can judge in a canonical trial that one is guilty of the DELICT of heresy and impose that judgment on the consciences of the faithful.  HOWEVER, that Church judgment must be based on the SIN of heresy.  If there is no sin, there can be no delict.  Whether one has committed the SIN of heresy is determined by his external acts of heresy.  These external acts can be observed AND be judged as a SIN by anyone IF there is sufficient evidence to attain moral certitude.  In this case, it would be a private judgment that cannot be imposed on another under pain of sin.  HOWEVER, if the other becomes convinced of the same, then his own conscience would bind him.