> Should one have to work so hard to make private methods?

In an open-source Java system, what happens when developers need
access to something declared "private" or protected?  Answer:  They
loosen the visibility to what they need and recompile.  It's not
"protection" at all (again, assuming an open system whose intent is to
be modified).  It's more just rigid "documentation".

In Squeak, methods in "private" category mean, "use only if you know
what you're doing, and at your own risk".

> It does nothing for other forms of protection, such as allowing ancestral
> access, sibling access, class access.
>
> Maybe that's not important, of course.

Well, it's certainly not worth the complications (just understanding
and remembering the subtle semantics is too much), and not conducive
at all to a dynamic system.  It literally is "early binding".