St Padre Pio's opinion on who is or isn't pope is irrelevant, as he is not infallible. Just as our opinions are also irrelevant. What IS relevant is that these popes hold the papal office, whether we like it or not. They are NOT good popes, as anyone can see. So, whether the post V2 guys are/were popes is irrelevant because a bad leader has the same effect (or worse) as no leader.