1) Politically. While most users don't care enough to stop using the service, users in the US and Western Europe care enough that politicians who stand up to FB get praise and potentially votes. Looking tough on tech is now a quick political win and that will eventually hurt them, most likely in the EU.
2) Talent wars. HN might not a good proxy for the general population but it's reasonable proxy for people FB wants to hire and the general sentiment around here seems to be I don't want to work for FB anymore. IRL most of my engineering friends don't want to work for FB either.