[Ctyra]

You answered your own question. If you are a manager, and you asked someone to get this information. You have enough oversight to know if the information was obtained through ethical means or not. At FB scale, if Zuck wanted this information, he has enough staff to flag unethical snooping of users. They did it because they wanted to do it even if it's not ethical, not because they didn't realize it's unethical.