It seems like you're being deliberately obtuse in your first two answers.
How so? They didn't do anything to hinder what you want to do whatsoever.
The easiest thing to do is to use Moose's automatically-generated new, which does the thing the OP doesn't want. AFAICT "attributes" are the product of confusion between the view that an "object" is a collection of named bits of state, and the view that an "object" is a box to which you send "messages." People want "messages" telling the "object" "give me the value of this named bit of state," so "objects" have "attributes" by default.
is => 'ro' is simply a shortcut for reader => $name, and is => 'rw' is simply a shortcut for accessor => $name.
But if you just do 
has 'foo';

[download]
You get read-only attributes by default. The OP's question is "why?" The answer usually leads to a religious war.

As for internal-use attributes, the OP is wondering what this does: 

package Base;
use Moose;
has 'x', default => 'Base'; # internal

sub foo {
   print shift->x;
}

package Child;
use Moose;
has 'x', default => 'Child'; # also internal

package main;
Base->new->foo;    # "Base"
Child->new->foo;   # "Base" or "Child"?

[download]
(I would test it myself, but don't have Moose lying around.)

In reply to Re^2: Psychic Disconnect and Object Systems by educated_foo
in thread Psychic Disconnect and Object Systems by John M. Dlugosz

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