Yep, I noticed that. I believe that changing the "number of days logs to keep" handles that automagically...did you try setting the days back to something less than they are now, and see if the system deletes the older logs for you? (I suspect that is what will happen).
That permissions setting is a "change" from the how they were originally set, and is a security measure (back "in the day" you could delete them). You can always ask Tech Support to delete them for you via a Support Request from the Control Panel.