If anything, the IA should be more reluctant to remove information without a court decision.
And that's a good thing in the vast majority of cases. Unless we're talking about sensitive information that was published without the consent of the person in question, all public information should remain public forever.
But there's some absolutely essential priceless diamonds hidden in the crap. And they can't be found/known at the time of collection: only with the future development of other events & knowledge do they become retroactively evident. So you've got to collect & preserve as much as you practically can, or else great things are lost forever.
Further, even the mounds/magnitudes of crap can turn out to be important for understanding the past. Ads that annoyed readers at the time help communicate how people, & businesses, & technology were really operating – not just the self-serving stories people craft later. The most-fumbling and awkward early uses of a new medium – hypertext, or RealAudio, or Shockwave Flash, or whatever – reveal enduring lessons about the evolution of technology & culture, including roads-not-taken that could still hold promise.
This shouldn't surprise us. Much of what we know of past civilizations comes from archeologists studying trash dumps that, via dumb luck, were well-preserved.
So if you tell me, "the Wayback Machine is a giant unedited trash heap of the internet", my response is: "Yes! That's the point! You get it!"