Can I ask about more abstract things here? For example, can I ask about why a DNS needs to be public? Or how a accessible public DNS creates a unique destination?
From the way I understand the meaning of these examples, the answer is most likely "No, you shouldn't".
We expect questions on SF to be about an actual, technical problem you face. Questions that amount to "please explain to me how X works" aren't a good fit here and can and should be answered with "Read a book" or "Read RFC xxxx". For your examples, there are excellent books available, BTW.
And also: "For example, can I ask about why a DNS needs to be public?". Who says that? Having a private DNS is entirely possible and quite common in larger organizations.
All that said: Thanks for taking the time to ask on Meta beforehand!