The time I've spent as a moderator has given me lots of opportunity and motive to think about how the rules themselves and the way we apply them could be changed to give people who stumble onto this forum more incentive to stop in and share their thoughts, ideas, and experiences. If I were granted one wish to change one thing, it wouldn't be to a rule as written, but to an unwritten exception to Universal Rule 4, which reads:
Do not "derail" threads or otherwise insert commentary that has nothing to do with a thread's opening post.
The unwritten exception is that posts that address a member's motive for posting are not considered derails. It's nothing new. I think it's existed since before I started actively posting here. But, in my opinion, it both permits and encourages interpersonal conflict that has nothing to do with the subject of most threads.
If you look, you can finds hundreds, if not thousands of examples. The effect is to change whatever the topic of thread happens to be into a dispute over the motives of someone who said something in the thread. It's common for the result to be the loss of the substantive conversation in the mess of purely interpersonal conflict.
In reality, unless we've all become telepathic, we aren't as good as we want to think we are at discerning people's motives from what they post here. Especially when it comes to a specific post. In most cases, all we are really doing is trying to change the subject when we can't or don't want to respond to the substance of post.
If one's goal is disruptive trolling, then the tactic can be used in an entirely malicious manner. One of the most effecting trolling tactics is to simply make up something as an accusation against another participant in the online forum. The intent is to force participants of the forum away from whatever they are interested in discussing into perpetually defending themselves from 100% accusations. And the troller doesn't care about the truth of their claims -- the point is to attack and disrupt.
If the exception were eliminated, people would still be free to discuss each other's motives for posting. But they would have to do so in a separate thread. Perhaps we could call it a "meta thread." Those interested in discussing the substance of the thread's topic would be free to do so without the disruption of trolling or interpersonal conflict. Those who want to discuss the motivations of other posters have a place to do so without the intrusion of substance into their discussion.