Topics may be closed for several reasons that I have noticed, however I an not the absolute expert
Often it's a duplicate thread
Or some highly offensive posts were made and may have been removed from view.
There are other reasons but the fact is you do not always get to see the posts that got it closed.
Sometimes. and this reason I AM an expert on.
I started a thread some time ago, forget where. but I got the answer, the issue was resolved and yet the thread went on and on and on and on and Finally I ask the moderators to lock it down.. They complied with what they clearly felt was my reasonable request (Thank you moderators if it was here).