Why do private member variables behaved like protected in the same module when creating deriving class?

[12345swordy]

On Friday, 26 October 2018 at 20:55:00 UTC, Jonathan M Davis 
wrote:
> On Friday, October 26, 2018 1:55:08 PM MDT 12345swordy via 
> Digitalmars-d wrote:
>> On Friday, 26 October 2018 at 19:45:48 UTC, David Gileadi 
>> wrote:
>> > [...]
>>
>> If it deliberate, then it needs to be documented.
>
> What are you asking for exactly? The documentation documents 
> exactly what the behavior is:
>
> https://dlang.org/spec/attribute.html#visibility_attributes
>
> "2. Symbols with private visibility can only be accessed from 
> within the same module. Private member functions are implicitly 
> final and cannot be overridden."
>
> Are you looking for the documentation to explain why there is a 
> "loophole" to private that allows other symbols within a module 
> to access private members of a class of struct?

No I am asking why class B inherent the private variables of 
class A that is marked private, when we have the protected 
keyword.

I don't know how else I can I make this any clearer.