I think it's interesting that a lot of 'seminal' or foundational texts, speeches etc. that enter popular culture as significant touchstones of a movement are actually, in their time, specialized infighting.→[More:]

I've ruminated on this here earlier [one, two] but I've been researching a lot on Malcolm X etc. and when you look at his foundational, famous speeches what are they really? Responses to his time, place and people. Same with, oh, "The Political Is Personal" Carol Hanisch, and "What Is To Be Done?" Lenin, the Federalist Papers, and so on. These things are just remarkably shaky ground to build on, but start gaining a force of moral authority that's almost unwarranted ["Original Intent", etc.]

The problem isn't just that they're scoped within a historical context--that's a given--but also that they're often extremely specialized. The words and phrases used within these speeches, documents, books are contemporary in-movement talk and don't really fare well when plucked and dropped outside of that understanding. What this does is eclipse the fact that they're just facets of an approach within a larger argument, struggle, culture and not necessarily that uniquely privileged in terms of veracity compared to whatever they were in contest with.