yes it is wrong, and she's reacting like this because she is baby-sitting your insecurity by acquiescing to this request, and that makes her angry that on the surface you dont trust her, and sad that her having access to her exes profiles and visa versa made you feel threatened or insecure about her attachment to you. It screams "CONDITIONAL LOVE " i.e red flag
The short answer is, if she was going to cheat on you or go back to her exes she would, with or without facebook, you cant assuage your insecurity by trying to regulate her life as a way to erase her past that you dont like.
To fix this you must do the opposite, talk about her exes as a main topic, tell her the truth tell her why you are so affraid of them, tell her the real reason you wanted her to delete all contact.
Good luck. Dont do this move again with a lady in the future just dont.
