Ah, then I see, too! We're talking about the thread topic appearing on every response.
I think I noticed a possible reason for that.
If we look at all our activity (or click on "Notifications"), and see the list of posts, the "Re: [fill in thread title here]" gives us a clear picture of which thread we were responding to. That helps us decide if we want to select it and go back to read or respond.
(Take a look at your activity page*, or look at your notifications to see what I'm referencing.)
So, essentlally, we have a "topic line" or "subject line" for each of our posts.
We have the option to edit this response-topic line, but if we make the "title" of our response 3 dots, or something else unrelated to the thread topic, it becomes a little confusing to look at our activity or notifications.
Not a big deal, but something I noticed.
(*How to find your recent activity: http://community.qvc.com/t5/Community-Chat/SIMILAR-TO-quot-MY-ACTIVITY-quot-FIND-ALL-PREVIOUS-POSTS/...)
Few things reveal your intellect and your generosity of spirit—the parallel powers of your heart and mind—better than how you give feedback.~Maria Popova