s runs the command dired-sort-toggle-or-edit
Toggle between sort by date/name and refresh the dired buffer.
Nice, but when we hit it we don't stay at the top of the list, but are
sent tumbling below, cursor glued to that former (often) first file.
Yes, a feature I know, but no way offered to start afresh at top
without adding stuff to ~/.emacs.
As you say, this is not a bug - it is by design. But perhaps the design
could be improved (made more flexible).
I must admit that I too have been annoyed by this. I've grown used to it, so
I work around it in various ways unconsciously.
The design is to permit the current line to stay in view, and that makes
sense in many contexts - in particular, if you have inserted subdirectories.
However, sorting the directory listing is an operation on the whole listing,
not on an individual entry, and there are other contexts (or work habits) in
which it makes more sense to redisplay the listing starting at the top.