There are lots of reasons that the Moderators close a thread. Most (almost all) have to do with violations of our forum rules. (See the link at the bottom of every forum page) When tempers get heated and the $hi.. starts flying, a warning to calm down is issued and a chance to change the tone. Usually this is short term fix, the posts go off the rails again, and it is closed. The actions of banning a member is never discussed in the open with the Forum members, it is an action that is only discussed by all the Mods. No one makes a decision on actions like this in a vacuum.
Guns are left to discuss until it goes off the rails, which is almost every time, given enough time, after several requests to stay on topic
Do a search on guns on the Forum and you will see that we do try to let these run and do not automatically close them.
We also close posts in the Classifieds when the item is SOLD as confirmed by the OP. This makes sense to not leave them open if the item is no longer available.
Same with the post this morning. The OP had requested for help with the purchase of a specific trailer that he was considering to purchase. In a different post also posted today, he stated that the original trailer had been sold and he had moved and was now looking at a different trailer and was asking for help with it instead. I closed the other thread, as commenting about it would not help him any more because of the change in his circumstances. Made sense to me, but I left it open if anyone disagreed with my reasoning and could give a reason to keep it open. Just send me a PM with the reason. The reason was simply to help the OP out to get help with his new questions and to avoid energy spent by the Forum on answering a dead question.
I hope that this explains what was going on behind the curtain. If not, I'm all ears, or in this case, all eyes.