Question…
“What exactly does the SSPX do that the Oratory, FSSP, and ICKSP, etc do not?”
Really, this question is the crux of the entire issue.
Response…
Vatican II and the New Mass. The SSPX, as such, says the quiet part out loud, that virtually all committed trad-Catholics believe. The other groups, while manned with many good priests (I don’t doubt this for a second), are in a position where they can’t do so.
Unfortunately, although not always, this means that various ED group associated publications, like Claves in France, will spend a lot of time going after the SSPX, but won’t utter a peep about the actual problems in the Church.
I know that, for many, this approach by various ED groups is seen as prudent — “if they speak up, we lose our Mass” –, and I get it. But, at a certain point, when the revolution becomes indefinite policy, you are kidding yourself that staying quiet will save you.
Also, there is a difference between the virtue of supernatural prudence and what is called “carnal prudence” or “prudence of the flesh.”
The latter is a natural virtue, which pagans can acquire, and it is a prudence, but with factors such as human respect, place in society, material goods, etc, as animating principles. Whereas, supernatural prudence is the Catholic version wherein the rights of God are held higher than the rights of man, and this is fundamental to all decision making.
At a certain point, one has to wonder, when is that line crossed in the wrong direction.
As Lefebvre masterfully said, “”At the hour of my death, when Our Lord will ask me, ‘What have you done with the graces of your priesthood?’ I do not want to hear from the mouth of the Lord, ‘You have contributed to destroying the Church with the others!'”
No, I am not saying ED groups are “destroying the Church” and I would NEVER say that.
Nonetheless, we are very far from the fog of war that loomed over the Church in 1988, wherein it was hard to see where lines were drawn, what the consequences would be, etc.
The DDF now openly attacks the Virgin Mary with the Pope’s approval, among many other things. It has become so common that we are almost desensitized.
At a certain point, you have to speak out as a priest or bishop, because Napoleon III is really only different in degree than kind: he still needs you to accept revolution, even if he lets you do it while looking Catholic.

