Thanks for writing this, puzzlegal. It’s beautifully written. I’ll bookmark it for the next thread like this one.
As I see it, there are two issues discussed in this thread. One can be fixed in the admin control panel and one can’t.
The issue with Discourse deleting the entire previous post if it’s quoted in its entirety can be fixed in the admin control panel. See here on Discourse Meta. One admin who turned off the feature soon realized how repetitive the site became.
The other issue is that Discourse doesn’t distinguish between replying to the OP and replying to the post above. That needs a change in code or a plug-in. The issue is discussed on Discourse Meta here. It’s pretty clear from that thread and this one that changing that feature is not a priority for the Discourse team since there are so many easy ways to make the communication clearer by quoting and context.
In both cases, any change would have to go through the admin on the SDMB…