Ultimately, in either direction, it comes down to intention.
"I am the Lord who search the heart and prove the reins: who give to every one according to his way, and according to the fruit of his devices." Jer 17:10
It seems to me that if SSPX has a valid doctrinal stance to begin with, piusv makes is a very good point.
If the issues they raise are the sort of thing that can be settled by tinkering at the margins there wasn't much reason for all the sound and fury surrounding SSPX in the first place. If, as SSPX asserts and most who agree with them insist, there are major doctrinal points at issue then how can they reconcile without those issues being addressed after they've come this far ?
Modernism/Americanism is without a doubt the major strain of thought in many if not most places in this country but I don't see how that being the case frees individual Catholics to decide they can do more than find a parish where it doesn't hold sway or at least doesn't totally destroy the constant teaching of the Church.
I honestly don't see much difference between Luther during the few years he remained Catholic prior to being excommunicated and most of the SSPX folks I've run into. Overall they seem to have gone far beyond what Lefebvre had as his goals. Both Luther and Fellay rationalize away their own disobeying of every bit as much Church Doctrine as they insist those they oppose are disobeying.
IOW, there's either One True Church or there's not. I think someone has to be blind or on some sort of auto-pilot to not see the damage Americanism & Modernism have done to the Church in this country but the SSPX route ends at the same destination as the "True Catholic Church", "Palmarian Catholic Church", and "Pope Michael" crowd, without doing much good.
Where's the line between Luther and the folks who tell other Catholics not to go to Mass at all unless they go to one approved by them, even to the point of calling the NO Mass "an offense against God" ?
Working to halt and reverse the rot is one thing, burning the village to save it is another.
Didn't Pope Benedict XVI reaffirm that the Traditional Latin Mass has not be superseded? Then why isn't the battle within parishes to have Latin Mass along with or in place of NO rather than calling the NO "an offense against God"? A characterization that doesn't to hold water given that the Byzantine and others are accepted along with the Traditional Latin Mass ?
JMHo