It's just a lie. She has no idea why nobody was posted on that roof. Nobody tells her anything and she's not in charge of anything. Like any deeply insecure diversity hire, she just made some crap up on the spot when she was given a question she didn't have the answer to.It's no excuse not to be on a roof. They are on the white house roof. It's got more pitch than any of those barn roofs.
They could have used local law enforcement to put a man on that roof. It would have been better than nothing.
They are supposed to be professional body guards.
I think this was all done on purpose.