We detached this subthread from https://news.ycombinator.com/item?id=25222895.
It isn't like Alexei & Jens working for a different company and implementing the same features would stop people using them. As TFA mentions, these are likely to be hot, high demand nuggets for many companies and developers.
Facebook has caused serious issues with society and it's not cool to just glaze over this any time their contribution to technology comes up.
This view seems quite reductionist. It's smells like guilt by association. It excludes the middle ground where you do not approve but ignore that due to other priorities (such as money or excitement about technology you get to work on). Approval is not a binary choice. It also is subject to tradeoffs.
So all you can derive from someone working at facebook is that their preference against indirect contribution (by several hops) to genocide is weaker than the combination of some other preferences. This may also be due to how they're discounting that responsibility distance.
Second, Facebook is not a tobacco or gun manufacturing company. Their main business is advertising, and they made several grave errors on the way, and they continue to do certain wrong things, but as much as you can hate them you can't morally equate any communication platform with planned genocide. It's shifting responsibility from actual people who commit attrocities to a platform that makes it easier for them to communicate. Yes, FB is easier to blame, but this approach misses the main point.
Personally, I have a few things I won't do, which are different from what other people won't do. In a certain "Overton Window", I don't argue about it.