If you think your identity could be stolen because of an unused email address, it might be your fault that's going to happen. Why would you register with an inactive email address and not check it? Email address seem like the main way for most people to login, if you have multiple, you must at least check them for something once every six months.
This announcement only says that they will remove those that haven't logged into their account in the last 12 months. Seems like a very long time in internet time.