IA accepts and follows takedown requests from almost anybody about almost anything.
Wow does it? I've seen some stuff there that is a definite target for takedown that seems to have been untouched for a while.
They go for security through obscurity and section 230 abuse.
Certainly, but many don't bother to check, let alone file for removal.
I went down an IA hole a month or so ago, and discovered someone uploading random Jaz + Zip drives images, that appeared to be backups from random businesses and people in the late 1990s There were diary entries, letters to a lawyer about divorce, business accounting data, invoices, and period-era porn, that if i were to guess, was organized to be offered on BBSes. tl;dr: encrypt that data at rest, you never know where it will end up.
I have mixed feelings about that stuff (which I've seen there too). There's historic value in it and I think it should be preserved. It also feels a bit icky and wrong for it to be publicly available so soon after its creation.
honestly, for stuff that old i kinda like the idea of seeding it anyway... i know that is a naïve PoV in the modern era, but i kinda miss the days of the internet being innocent enough that you got a real slice of someone's life sometimes.