Shouldn't the Topics RSS feed just show the recent topics? If thats not the case it should be renamed to Posts RSS feed.
I see now that the Forums RSS feed shows just the topics...
Shouldn't both be renamed to:
Forum RSS feed > Topics RSS feed
Topics RSS feed > Posts RSS feed
Forum page is a list of topics, so Forum RSS is a recent topics list.
Topic page is a list of posts, so the Topic RSS is a recent posts list.
This is the only reason why the button have such names.