I really don't want to say this but, the real names policy does help in terms of trolling behavior for certain communities. When TechCrunch switched over from Disqus to Facebook comments, the amount of trash and trolling was immediately reduced and stayed at a minimum permanently. A lot of the media outlets (Motherboard, Vice, NPR) who've disabled commenting altogether were using Disqus. I've noticed media outlets th…
However, you are also completely wrong. I'll produce two anecdata points.
Look at the Facebook comments on a local newspaper that uses them (e.g., thestate.com). Note that on any article that touches on a partisan issue or a scandal, the tone and contents of the comments are vicious, personal, and frequently harassing.
I admin a large-ish meme page on Facebook. The comments section is a wretched hive of scum and villainy.
From what I can tell, some communities have better norms than others, in terms of promoting civility, but the use of real names doesn't make a significant difference.