No, it doesn't steal your password. It needs to log in (appearing offline) because your contact list can only be retrieved when you are logged in to your account with your email-address and password.
In short: To gather the information, eg. Deleted list, Allow list etc, the program needs to log in with your email and password but it won't steal any of your infos.
(Btw, NoRooms new listmanager is available
here)