None of the saints ever supported any papal claimants that were unorthodox in belief or practice. The papal claimants that the saints supported were not heretics. There was confusion over who the real popes were, but there was no confusion or question about the Catholicity of the claimants.
Big difference from the current situation.
You are so right about that, there is a big difference between an anti-pope and NOpope. Anti popes were Catholic. We have had popes also that were personal sinners, but they too were Catholic; they did not
lead the church into false ecumenism and other errors.
What you see today is a man sitting in the Chair of Peter, who is leader of Truth (SSPX) and False (novus ordo), SSPX et al teach
the Faith, which is the most important in salvation. At least with sedevacantism, CMRI also teach the Faith. I honestly can't say much about other sede groups, and have serious doubt about Dimond being within the Church, (my observation and opinion).
My own personal opinion
again, is that God wants the SSPX right where He has them. Because there are still many people trapped within the novus ordo who are not ready to accept SV for some reason or another, they take baby steps, and find SSPX to be their SUPERNATURALlifesaver
. SSPX I believe have an important roll to play, in that they can reach many people, who can not stand to hear the Chair is empty, they can offer these people Faith, and the sacraments.
Someday however, SSPX and SV will come together, because sooner of later, people in the world will realize, in God's good time AND GRACE, the truth of the situtation. That again is my opinion for what its worth. Just so there is no misunderstanding, I am not saying I have more grace because I am SV, I don't know why I can see this and others can't. Maybe God, just wants me where He put me for His own reasons.