Confused about what the COMMENT keyword means

[Alain.Cochard@unistra.fr]

Hello.  I have the file:

   * COMMENT foo
   #+EXPORT_FILE_NAME: foo.pdf
   #+TITLE: foot
   fofoo
   * bar
   #+EXPORT_FILE_NAME: bar.pdf
   #+TITLE: bart
   babar

If I do 'C-c e l p', the file 'foo.pdf' is created from the 'foo.tex'
file.  The content is bar'ish, though, as I expect.

By contrast, with this file

   # * foo
   # #+EXPORT_FILE_NAME: foo.pdf
   # #+TITLE: foot
   # fofoo
   * bar
   #+EXPORT_FILE_NAME: bar.pdf
   #+TITLE: bart
   babar

for which I explicitly comment the whole 'foo' tree, the content is the
same but the files are 'bar.pdf' and 'bar.tex'.

But I thought both way of commenting were equivalent.  What am I
missing?  Thank you.

NB: I used 'emacs -Q'

GNU Emacs 27.2 (build 1, x86_64-redhat-linux-gnu, GTK+ Version
3.24.30, cairo version 1.17.4) of 2021-08-07

Org mode version 9.4.4 (release_9.4.4 @
/usr/share/emacs/27.2/lisp/org/)

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