However, it is a fact that some literature is pernicious and subversive. Why else would we have had the Index?

So, would you place De Romano Pontifice, by St. Robert Bellarmine - a Doctor of Holy Church - on the Index?  Is it "pernicious and subversive"?  No, and the same is true of ALL the pre-V2 writings used to support the ideas which provide the basis for rejecting the V2 anti-church and its anti-popes.  Even if one disagrees with such claims, to say there is no reason to consider them in these wild days, or that the idea itself is harmful makes no sense (even if one claims that the conclusions of sedevacantists are incorrect).  Everyone - and I mean EVERYONE - who rejects V2 and the catastrophic changes it brought about in our holy religion is, in principle, relying upon similar principles.  We ALL agree that what has been emanating from Rome these last 40+ years is non-Catholic garbage, straight from hell.  That is why we do not participate in it.  God speed, my lady.