FDL again, was: My concerns about GPLv3 process

[Alfred M. Szmidt]

   Why is different the "free" as in freedom concept for documentation
   from the concept of "free" as in freedom for "software"?

It isn't that different, the four freedoms still apply.  The
difference is that the content isn't a functional work, and one may
wish to attach a dedication to the text, or maybe something else that
isn't related at all to the actual text.

   Why does FSF have two distinct opinions about the adequate level of
   freedom for manuals and for software?

Because they are different.  It is that simple.
http://www.gnu.org/philosophy/free-doc.html

   There is no doubt that free software needs free documentation, even
   FSF says this. If so, why does FSF allow restrictions to
   modifications of documentation (using FDL) that does not allow for
   software?

Because such restrictions make sense, you don't need the right to
modify my thoughts about why I wrote the book, or to whom I dedicated
the book.

   There is people that thinks software is the conjuction of programs
   and their documentation (and other thing, like images, etc.). For
   example, Debian project seems to think this way.

Debian consideres _everything_ software, which is simply bogus.  Some
images might make sense to have as verbatim only, same applies for
many texts about philosophy, or even music recordings.  This does not
apply to functional works, like software, where modification is an
essential right.

You don't need the right to modify my poem about dragons, or infact,
this text.

   Why limit modification of documentation of a free program, if we do
   not want that limit for the program itself and if the documentation
   is necessary?

You aren't limited anywhere when you modify free documentation of a
free program.  This is like saying that you are limited by the GPL to
create non-free works, which is simply nonsense.

Cheers!