Technically, a dogma doesn’t HAVE to be defined by an
ex-Cathedra statement. All that is necessary for a teaching to be a dogma of the Catholic faith is that it be taught solemnly even in the encyclical letters of a pope. This is the infallible “ordinary” magisterium. While I can’t take a position on the claims of many SV’s, their objections are much more serious and scholarly than their opponents give them credit for, and, no, most of the quotes of former popes are not taken “out of context” by them.
Given the current situation in the church, I think it is possible for a person to be an SV in good faith and without malice, even if they are mistaken.
Love, Jaypeeto3