Pages such as the /Secure/Login.aspx page and /Admin/*/.aspx are all physical pages that live on disk and are not pages that should be indexed by google and have no SEO value in your site so it matters not whether google sees that url as upper or lower or mixed case.
The urls match the actual case of the files and folder names on disk whereas CMS pages (which are virtual and do not correspond to files on disk) do use lower case by default to keep it simple.
On Windows the file system is not case sensitive so the url /Secure/Login.aspx is equivalent to /secure/login.aspx but we use the real actual file system case because on linux the file system is case sensitive so to support running on Mono/apache/linux the case of urls is very important and must be correct for physical file or a 404 will result.
Hope it helps,
Joe