Linux copies permissions from UNIX.
That system was designed for security in the Main frames days when Computers had many users.
Microsoft started as DOC then windows. Single user un-networked PC's. They are trying to achieve something. But are hobbled by backwards compatibility issues, changing focus, and not will to force programmers to do it correctly. ( know of any Microsoft Docs on the subject.

Note the Windows Vista is harder to lock down then XP was ( or so my coworker yelling Microsoft Sucks leads me to believe)