If the materials were publicly available on a site and scraped? Fair use.
If they were distributed illegally and acquired through that distribution? Cooked.
If you scraped it AND saved it? Cooked.
The only exception would be a very small startup, which isn't the case here, or all IT, admin and engineering staff told the company they aren't doing anything illegal for Zuckerberg. That's not going to happen at Meta either.
Maybe an ethically bankrupt company with a "move fast and break things" ethos looking for exactly the plausible deniability your comment hints at?
Well now I'm hoping this makes it to a courtroom, so that the plaintiffs can ask, on the court record and under penalty of perjury, exactly what he was using that quantity of pornography for. When, how often, and so on. (Not that there's anything wrong or shameful about that, in general, but it would confirm my biases about what executives do all day.)