File Permissions in Nautilus

Obviously, people that say it's easy to understand recurivity actually don't understand it. You didn't understood or explained recursion AT ALL.
Especially since what you describe is :
- plain wrong and false
- describe inheritance at best, which is not at all how it works

In case you wonder where your description is completely wrong :
if you have, say, a root only owned file or directory in your home, you can be sure permissions won't be applied to them at all.
You have to use recursion to describe the mechanism correctly, and immediately, it's way more complicated to understand that what you describe, even though rather easy to describe.