I wonder what this means for people I know with accepted offers who haven't yet started.
But it might depend on whether they were pre-allocated to a team (which I understand is very rare, but it does happen).
People in the real world use instagram and whatsapp all the time without any moral qualms. The main reason facebook as a product is on a decline is because it is simply not interesting to younger people anymore. And even then, FB still manages to occasionally produce features that capture a lot of the audience back. FB marketplace has been a great hit in terms of replacing craigslist.
I am not a Meta employee, and have never been one. But the hate hard-on some people on HN have against Meta just gets really ridiculous at times. We decry echochambers on social media all the time, but are perfectably comfortable falling into ones of our own, without trying to understand how the world outside is really like.
I agree with your take on ethics courses being mandatory for CS or engineering college students though. It was mandatory at my college, and I found it to be pretty useful.
EDIT: as pointed out, i incorrectly used "contract" instead of "contact" in the first sentence. Fixed, as it doesn't meaningfully change my point at all. The part relevant to the point I was making was in the "... because Meta is causing irreparable damage to society" half of the sentence.