Perhaps.
OTOH, having posted in response to a series of posts part way into the thread, (posts submitted before the nasty personal shots really got under way), your solution offers me only the options of failing to deal with the trainwreck or going back and erasing my last post.
I suppose I could delete my post, but I see no reason to do so.
In the last instance, I made a totally neutral GQ/Straight Dope observation that did not bear on any of the anger in the thread. In this case, I posted another GQ/Straight Dope observation, although one closer to the actual core of the topic, at the time I encountered the posts that prompted my remarks, then, a quarter hour later, after finishing reading the thread, (indeed, after at least one other post had been submitted), I made a Mod call. To describe either situation as one in which I was having the “last word” and then slamming shut the thread is odd. To describe this thread in that way, when I was not even the penultimate poster, is beyond odd.