Does anyone know how to get in touch with the administrators of Spotted at Mac? Do I send them a private message? I don't want my message to show up on the actual page lol.

You mean the facebook group? Didnt you just answer your question regarding privacy with the solution of a private message? I dont see what additional guidance you require when your answer was included as part of your question..

If it's a Facebook group then only way to message the admins is to do so via facebook private message. It wouldn't be anonymous, but it wouldn't show up in the group