Why do you need to log in?
Every time we request information from Twitter, this has to be done on behalf of a Twitter user, so every time you want to see information that requires a request to Twitter, we need to be able to make this request on behalf of your account.
If you have logged in you can always revoke access from our application, or any other application, to your account on Twitter by clicking the following link:
twitter.com/settings/applications