The following is only about interacting with a Discourse forum via email.
Email and forums have different conventions. When someone replies to an email, they expect it to go just to the person being replied to. When someone replies-all to an email, they expect it to go to the whole forum / mailing list.
I’d really like to see the option where an email “reply” just sends a private message to the person being replied to, whereas “reply-all” adds the post to the topic.
Some context: a user wrote to me about getting too much email. They were pretty angry when their “private” complaint got emailed to the entire forum / mailing list.
For one community I wrote a plugin that adds the user’s actual email address to the message so that they can email them directly. Since your users seem to want a 1990s era mailing list, that might be what you want to do.
I think that it’s also possible to include a button that will let them compose a PM in a web browser.
Yes, we’ve recently migrated from a mailing list from the 1990s. Ironically, the previous mailing list also had “reply” go to the entire mailing list, so they are requesting a change in behavior.
Users can have some peculiar requests. In this case, I agree with the user that Discourse should follow email conventions when interacting via email. I made a similar feature request to Discourse Meta for stripping “Fwd:” when creating a topic based on a forwarded message: users won’t - and shouldn’t have to - break email convention when forwarding an email to the forum.