Their schismatic belief that one may knowingly receive sacraments from heretics and schismatics, contrary to St. Thomas, Galatians 1:8-9 and Titus 3:10-11 and Catholic common sense and constant tradition.
Their heretical belief that canonizations are to be held as ex cathedra dogmatic definitions, contrary to Vatican Council, Session 4, Chapter 4, paragraph 6, decreed by Pope Pius IX (For the Holy Spirit was promised to the successors of Peter not so that they might, by his revelation, make known some new doctrine, but that, by his assistance, they might religiously guard and faithfully expound the revelation or deposit of faith transmitted by the apostles.);
Their schismatic denial that validly baptized children who are born and raised in heresy are schismatic upon attaining reason and free will, since at that point they are immediately bound by the divine law (including the law to profess the true religion and be subject and obedient to the Roman Pontiff), which not even the Church can dispense them from, and it is unlawful for the Catholic Faithful to presume invincible ignorance. The Dimonds basically argue that Protestants above the age of reason can be "Catholic without knowing it", while adhering to a sect that rejects the Catholic Faith, and subject to the Roman Pontiff, despite being subject to a religion that rejects the papacy.
Their heretical belief that the limbo of infants exclusive of fire is not only not heresy, but a dogma, by twisting Auctorem Fidei #26 into something it doesn't actually say and attributing to it greater authority than it wields and by making assumptions about the Council of Florence, Session 6 (But the souls of those who depart this life in actual mortal sin, or in original sin alone, go down straightaway to hell to be punished, but with unequal pains- which they translate as "punishments of different kinds"), which are contradicted by the Council of Florence, Session 11 (all those who are outside the catholic church, not only pagans but also Jews or heretics and schismatics, cannot share in eternal life and will go into the everlasting fire...- unbaptized children are part of the "all those who are outside the catholic church").
Their adherence to the line of antipopes beginning with Leo XIII and including the antipopes Pius X, Benedict XV, Pius XI, Pius XII. Are you aware, by the way, that the Dimonds actually believe that Benedict XV, Pius XI and Pius XII are true popes AND heads of the beast mentioned in the Apocalypse of St. John!?
With all of these errors and monumental self-contradictions, it is no wonder at all that the Dimonds do not teach the necessity of specific abjuration for converts from heresy and schism.
What Must You Do To Get to Heaven?