i was wondering why didnt WordPress have a better or custom privacy settings, to include things like "unregistered people cant see my blog" to "Custom user types and restrictions".
I think in general - and this is just my opinion - that most people who use WordPress probably want people to have access to their site. Concentrating on building a lot of privacy features into a blogging platform or CMS might seem counter-productive if the purpose of blogging or having a website usually means having it open to the public and wanting the traffic.
That being said, there are a lot of people who enjoy having sites that are only available to friends and family as well. I think that's probably why there are so many plugins that allow you to restrict user access, modify roles and capabilities, and generally make your blog private if that is what you want to do.
The use of plugins usually allows you to extend WordPress in a way that lets you customize it's function to suit your needs. It just may take a bit to find the ones that work the best for you.
Have a look at this one - Private WordPress - and maybe it will spark some ideas about where to look in the plugins directory for what you need. Here are some other search ideas;