Default theme missing ‘comment_form’ action?

The <?php do_action('comment_form', $post->ID); ?> line doesn’t appear in the Default theme’s “comments.php” file, though it appears in the “comments-popup.php” file and in both of those files for the Classic theme.

Is that on purpose? Or is it a booboo?

(sorry I keep saying booboo, it’s just such a good word ?? )