It's mountains of misery of never ending trolling topics that are controversial, will never be solved, and are meant to incite and start wars. The signal to noise is overwhelming negative, has little or nothing to do with tech political and moral issues, and much is banal, uniformed opinion at a low level of sophistication due to the nature of the medium.
I hear that that's your opinion, but as frustrating as the PRSI has been from a moderation and administration point of view, I'd still like to attempt to balance that view a bit.
My version of your statement: Users will have no trouble finding trolling, bickering, and insults in PRSI, but they'll also find well-reasoned, well-balanced posts and be exposed to multiple views on topics. I know this because in the course of moderation, administration, and researching potential moderators I've read quite a few posts and threads there through the years. So while I'll readily admit that what you write can be true, it's certainly not a complete truth.
There's no rule that says topics there have to be tech-related, and my impression is that many users who get to each other in the tech-related forums enjoy discussing other topics with each other.
As to uninformed opinion at a low level of sophistication, I'd say that democracy is hard ;-) and that even among educated individuals, my experience is that opinion about the relative level of sophistication in a discussion can at times be surprisingly subjective. I'm not saying that MacRumors itself is a democracy; it isn't, it's a private site with a set of rules that attempts to strike a balance among many variables. But on a site as large as this one with users from many parts of the world who have varying education and experiences, it seems perfectly reasonable that users would disagree about PRSI topics.
If I'm tired, hungry, or need more caffeine, I can get pretty disgusted at some of the behavior in PRSI. I don't have a lot of respect for taunting, trolling, or insults in any context. But in general I tend to think that while not perfect, the rules are a very good framework for keeping things on the right track, and quite a few users in PRSI are truly interested in discussion and are able to discuss respectfully if they so chose.
It is actually a choice to post an insult, it's not something that just happens. There's no evil posting fairy who gets users in trouble by posting nasty comments for them. It's about taking responsibility for what you yourself post. Leading by example is a good thing.