Why is the argparse module so inflexible?

[Roy Smith]

In article <mailman.3980.1372480662.3114.python-list at python.org>,
 Terry Reedy <tjreedy at udel.edu> wrote:

> > So a library that behaves like an app is OK?
> 
> No, Steven is right as a general rule (do not raise SystemExit), but 
> argparse was considered an exception because its purpose is to turn a 
> module into an app. With the responses I have seen here, I agree that 
> this is a bit short-sighted, as inflexible behavior. The tracker issue 
> could use more review and comment.

What is the tracker issue number or url?