Just keep in mind that just because Fr. Joseph Pfeiffer says something, it doesn't make it true.
Unfortunately.
Sad, but true.
When your whole argumentation is convincing, but founded on a lie, then what?
You're right though, I don't want any Pfeiffer propaganda on my forum. His rhetoric is false more often than it's true. It's not worth confusing people or blackening the name of good priests and bishops fighting Modernism and carrying on the fight for Tradition with no compromise, like brave honorable warriors.
Thomas A. Nelson taught me in Catechism class something you might want to learn -- that it's absurd to consider a man who loves his wife, is a kind father to his children, pays his taxes, goes to Mass every Sunday, helps old ladies cross the street -- but he's a hit man for a living! That simply doesn't happen.
Our Lord had something similar to teach: judge a tree by its fruits. Men don't gather figs from thistles.
You're not going to have virtue anywhere and everywhere, fidelity to the Cross, to a priestly vocation, wisdom in so many things -- except for THIS MORTAL SIN OVER HERE. That just doesn't happen. There's a principle in Catholic moral theology -- "no one falls all the sudden."
St. Therese the Little Flower when she was alive, or anyone habitually avoiding mortal sin, isn't going to OOPS fall into a grave sin of theft or murder. There would be lukewarmness first, dereliction of duties, skipping prayers, etc. which would lead perhaps to a large fall.
It's the same with priests. They first stop praying so much. They stop saying their Breviary. They loose the taste for spiritual things. They start looking for consolations in creatures and created things. They start hating to wear the cassock -- and it's all downhill from there.