Is there any good reason why C++ namespaces are "closed" in D?

[Manu]

On Thu, 2 Aug 2018 at 02:05, Walter Bright via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
>
> On 8/1/2018 11:08 PM, Manu wrote:
> > We have demonstrated consistent ongoing issues and frustration for 6
> > years.
>
> Have you ever tried the alias method I proposed?

Of course, it's the only tool we have here, and a major source of my
frustration!
Every time I type alias this way, I have thoughts that make baby Jesus cry.