And Christ, what about Christ?
He promised that the faith would not fail Peter, and that whatsoever he bound on earth would be bound in heaven.
The mere fact that heresy and error came forth through the post-conciliar Magisterium and these "Popes" is an indication that the Holy Spirit is not with them, that faith has in fact failed the successors of Peter, and that Christ is fine with contradictions being bound by this authority. All of which go against the indefectibility of the Church, therefore showing that either the Catholic Church is not the true Church of Christ or that the hierarchy is false.
The mere existence of a traditional movement is an indicator of this fact.