In fact: Because some people, for some reason, feel the need to set
"Reply-to" to their own email address: I've a procmail rule that
resets those to the mailing list.
That is rude and arrogant and you should *never* do that.
[snip]
That is your opinion and you're welcome to it. Mine is that
conversations begun on a mailing list by default should stay on the
mailing list.
By default, I absolutely agree, but that is not what you said that I replied to.
You said you intentionally set up a promail rule to OVERRIDE A USERS EXPLICITLY SET REPLY-TO.
Not even in the same universe.
Years of experience on a wide variety of mailing lists has taught me
there is a subset of participants that, for whatever reason, set their
default Reply-to to themselves, then expect respondents to "Reply
All."
That is *their* problem, why make it yours?
I rarely use "Reply All," and *never* on a mailing list.
The only time I do is on broken mail lists that:
a) don't have List headers, and
b) are configured to reply to the sender instead of the list.
Then I Reply all and delete the Senders address - but I generally tend to avoid such lists like the plague.
How Reply-to should be handled, or whether it's handled at all, is a
fairly frequent, and often contentious subject on mailing lists.
There is a huge difference between the reply-to-list munging argument, and what you are doing (explicitly overriding a senders explicitly set reply-to).
If you cannot see the difference then I guess we have nothing more to discuss, because I don't (try to) discuss things with stupid people.
As for the mailing list's policies: If they wish to allow un-subscribed
individuals to post, don't wish to set Reply-to or whatever: That's the
list's business, IMO. I'll happily work within the framework they so
graciously provide me 
Agreed... assuming I really want the content of the list in question.