You can post something on your wall directed at anyone without them knowing unless they are your friend. Only friends can read your wall if your privacy settings are like most.
My friend has called Obama an a**hole, but Obama can’t read that. However I can, and could rat him out.
I doubt you used the word “you” in your post directed AT Obama.
She was venting to these people as if they would be able to personally read her comments directed at “you”.
So again, why did she add them as friends? They don’t sound too friendly.