Well said, Michael. Thank you for your well thought out post.
I saw this post earlier and was going to respond later with a very similar post as yours; however, time constraints have been an issue for me today.
The mixing of topics becomes subjective, when trying to decide if the topic should be moved to another board or leave it where it's presently posted. In addition, as moderators, we don't always have time to read every topic, which is something you eluded to in your post.
In lieu of reporting a topic that a member feels should be moved to another board, they can also email me or any of the moderators with their request. I frequently receive such requests via email; however, I don't always move the topic.