There's nothing controversial here — Elsevier merely bumped up the rate at which they're sending Academia.edu takedown notices for obvious infringement by its users.

What's more interesting to me is that ResearchGate, a site which is virtually identical to Academia.edu in its "mission" and design, has been redistributing a shockingly large number of Elsevier PDFs for a long time. Unless these google searches are misleading, there seem to be many thousands of them:

https://www.google.com/search?q=site:researchgate.net+filety...

https://www.google.com/search?q=site:researchgate.net+filety...

I'm really stumped as to how ResearchGate gets away with this, but Academia.edu is getting hit with DMCA takedowns. Maybe Elsevier and other publishers haven't yet learned to reliably "find" ResearchGate's shared papers, or perhaps they've come up with some arrangement that allows them to publicly share thousands of paywalled PDFs with impunity?