The only problem here my friend is this: Unless the person belongs to the Novus Ordo, they have indeed judged him as a heretic already... and resist him, or separate, or just flat deny he is the pope.
Judging him as a heretic is not deposing him for it - unless one has first inflicted themself with dogmatic sedeism, in that case, judging him a heretic means he has self deposed.
St. Robert here teaches the Catholic principle, in the Great Sacrilege, Fr. Wathen expounds on this principle superbly:
...Catholics must be convinced of the following most important principle, a principle which has a special relevance in the context of this present writing. It is this: No matter what may happen, since no one may justifiably command another to sin, and since no one is permitted to obey such a command, no one may ever blame another—even an errant pope—for his sins. Conversely, the failure of any person—even the pope—to keep God's law or to preserve his own faith, does not excuse any other person for his failure to do the same. Ignorance of the law or ignorance of the Faith is never an excuse for sinning; one is bound to know when he is being commanded to sin. The notion is abroad that one may always simply follow the pope and the bishops and thus be sure of salvation. Ordinarily this is a reliable norm. However, it is so only because ordinarily the pope and the bishops are more zealous for and more perfectly instructed in the Faith than their subjects.
Neither can anyone get permission to sin through the erroneous teaching of the pope or any of his other spiritual superiors, nor through their failure to teach what they ought. Everyone is bound to keep God's law and the Faith....