Best answer by Mathis
Sorry about the delay in responding. Hmm, not exactly sure what might have triggered for you to follow your Facebook connections to be honest. If you have disconnected your account from Facebook now, even better. You might want to check the "connected apps" in your settings.
Other then that, sorry about the warning when you wanted to unfollow those users. Our Trust & Safety team had to place specific limitations on a set of features due to behavior that was considered "spammy" by some users. You can find further info around this here. Hope this helps in explaining why you saw the warning.