It's interesting to see that real name policies can actually make trolls behave more aggressively. On the other side of the spectrum, I anecdotally find that they actually prevent me from posting constructive things. I frequently refrain from leaving reviews for restaurants and stores on Google because I don't want them associated with my real name. It's not that I would otherwise be leaving low quality or bitter reviews, I'm just not particularly interested in anybody who knows my name having access to information about where I shop, what I eat, etc (even though I would be happy to share this information anonymously to help other people make informed decisions). I feel similarly about commenting on news articles, blogs, and apps that I use. It wouldn't surprise me if this was a significant factor in how real name policies affect overall comment quality.

Thank you for the link providing non-anecdotal evidence that a real-name policy does nothing to discourage aggressive trolls. I run a Facebook page with a moderate number of likes (~75K), and the fact that the trolling was, if anything, louder and nastier than in a comparably sized community on reddit, was one of the first things I learned.

I imagine it's because those trolls still have no consequences to their actions. If people would make more public the comments of those who are the most toxic (death/rape/other violence threats, etc), by, say, sending those comments to the person's mother/grandmother, their boss, etc, and they actually had consequences for those actions, then it might taper off.*

* Of course, this kind of action can have some far reaching consequences, and is quite ripe for abuse. I don't know if there is a way to fix that. And myself, not being the target of such abuse online, I'm not really that invested in trying it.