I'm a Thomist. I believe in Baptism of Desire and of Blood, which is taught by the Catholic Church under His Holiness Pope St. Pius X. The Anti-Modernist Saintly Pontiff who combated that great heresy. Hence, it is absurd - and heretical - to claim that BOD/BOB is heresy.
I firmly oppose Dimondism. Dimondism is the denial of the de fide doctrine taught in Trent and its Catechism that Baptism of Desire can justify and save. I am with St. Thomas in believing that God will bring all His elect to explicit faith in Christ for their salvation. I would even be open to the Augustinian theory that God, in addition, will bring them to Sacramental Baptism, if it weren't for the absurdities and extremism of some like the Dimonds. The Dimonds take pleasure in damning souls. That's obvious from their videos. That has never been the teaching of the Church and was not the opinion of St. Augustine either. The Dimonds anathematize 99% even of Catholics. They would be schismatic on just that count, to the exclusion of all other things.
Trent and its Catechism did teach the Doctrine of Baptism of Desire, and of Blood, which is the most perfect form of Baptism of Desire. That is plain, and has been the unanimous reading of Trent for 500 years. Not even Fr. Feeney or SBC today denies that Trent teaches that Baptism or its voto justifies. The voto of Baptism is included in the Baptism of Blood, because Martyrdom itself is the Perfect Act of Love. God loves everyone and gives everyone the chance to make Perfect Acts of Contrition.
It is difficult, but not impossible, for good-willed non-Christians to do so. If they persevere in doing so, they will be given the Grace of Catholic Faith, and Catholic Faith in Christ, before their deaths, and so be saved as Christians.