That's exactly why many don't run the official Facebook either. There are third party apps using the web-interface meant to sandbox Facebook so they can't gather all information. Up until now those web-interfaces have also been able to use the chat though. And you can still do that with some quick apps made to work around this block by facebook.
Also I'm on iOS so I can deny access to Gps/location/camera/mic and there's no way to access my message history.
Thanks for the reply though!