HA!
So you get to define the terms of the “Teaching of the Church”?
Ex Cathedra means something.
The fact of Popes who failed in human conduct does not raise their failings to Doctrine.
Luther did NOT begin by fighting against the sale of indulgences, as that was an afterthought.
As noted in the article, Luther was promoting a new theology, which he at first insisted was in line with Catholic teaching.
In a 1516 letter he firmly acknowledged the primacy of the Pope and the authority of the Church and sought to debate certain matters with a Cardinal, asserting that he would concede to Church authority after having the debate.
Luther lost the debate, but rather than follow his promise he appealed to the Pope.
When the Pope refused his appeal he called for a ruling by some future Church Council.
Having failed in his final appeal, rather than stand by his earlier ascent to Church authority, he wrote on 11 Dec 1518, his belief that the anti-Christ was rules at the Papal Court.
Interesting how _every_time_ people point out RC error, it’s dismissed as somehow excusable, misunderstanding, not doctrinal, etc - even when it’s absolutely central to the theology. After decades of discussion, I’m largely given up on trying to have a sensible debate precisely because every allegedly rock-solid point of doctrine suddenly becomes slippery & malleable when any valid point is made against it. Small wonder Luther gave up trying to debate the issues: he went in with a sense of what constituted rational fairness, and (if anything like the experience many have) came out of the debate feeling cheated instead of enlightened.
If this is the standard; then FR sure has a LOT of little luthers that are claiming the same thing about Francis!