I find deleting to be slightly easier than copy & paste in order to include the original sender. Further, what difference does it make to you how many copies the original sender receives? If I happen to receive two copies of a response to me, I delete one - actually I delete both once I'm done with it.
exactly;
this requires having to delete the extraneous e-addresses
Time is not the issue. The issue is, what does the RFC say? RFC's determine how things work, and how things will operate together. The primary problem as I now see it, is that there is apparently no companion RFC (or at least nobody has mentioned it) that specifies that email clients need to include a "Reply to List" button. That's an oversight. Someone with the skill and knowledge to amend RFC's needs to make that correction so that the next versions of all email clients include the button.
Therefore, I'd like to know what is the time savings in this vs.
having the reply go to the list ???
That's something I agree with, is one of my pet peeves and you've stated the case perfectly.