But there are countless small and large websites and app that collect private information, perhaps even more egregiously than Facebook because they're not in the limelight.
Why is that not a security risk? If it isn't, what's the minimum number of users you should have before you start becoming a risk?
There have to be some standards and arguments to justify a blanket ban. Just weaving the "national security" wand seems, to me, inconsistent and dictatorial.