While this is true, when the topic moves to something completely different than what the title of the thread implies, we have to either get it back on track, or shut it down. Nothing is more frustrating for a new (or old) user who clicks on the thread expecting one thing, and finding something completely different.
I think there is a Fine Line sometimes between trying to Minimize the possible Frustrations of people clicking on threads verses causing Frustration of people who are Contributing to a thread.
Because Threads can evolve over time as New (Related) Topics are Explored and Discussed. Or when the Original Topic has been Full Discussed. Or when New News or Information has be released.
Some Topics also aren't all that Earth Shattering. And people just want to have a Little Fun when a thread is done running it's course.
I think something that Compounds the Problem sometimes is a desire to have only One Thread where a given topic is being discussed. By Closing secondary threads, sometimes people are forced into 1 thread where it is Almost Impossible to limit the discussion to Purely the thread topic.
Like I said, I think for the Most part, the Moderation on the ECF is good. But a Lighter Touch in some cases would be Welcomed.