I could be wrong, but this doesn't seem to me to be a consistency problem so much as a difference in principles.
A Sedeplenist cannot believe that the Novus Ordo is *inherently* invalid. If its at least potentially valid, a priest like Fr. Hesse (a traditional and knowledgeable priest) would presumably have the know how to make sure, for sure, that his ordination was valid. Thus, on Sedeplenist premises it seems intrinsically believable that Fr. Hesse's ordination could be certain.
On the other hand, on Sedevacantist premises the new rite of priestly ordination is inherently either doubtful or outright invalid. Based on that premise, not even a traditional priest ordained in the NO who looked carefully into their ordination could be *sure* of their ordination, thus for a Sedevacantist it would be safer to avoid them.
I'm not seeing logical inconsistency from either party here. I'm seeing each party carrying their own premises through to their own logical conclusion, and then I'm seeing Stubborn call 2Vermont inconsistent on the basis of a premise she doesn't hold (namely, that its even *possible* to be sure that an NO priest is validly ordained.)
Am I off base here? If so, why?