Well put. I view them quite similarly, actually.
In fact, I'd take it a step further and say that they help the community in the grand scheme of things, as they give us all something to hate. A common enemy, if you will, that we can all come together to talk shit to, and though it may seem mean or rude in some instances, our actions are repeatedly justified every time they attempt to speak up in defense, or, better yet, when they attempt to attack another's character.
For example, in a world without trolls many forum sites die - luckily this is much more than a forum site - as the members soon lose interest in the small talk and the flurry of uninteresting threads (of which I know I've certainly created). However, when they do enter the scene, the community then can come together, and run that dirty mother fucker out. Then, when that goal is achieved, we can all look back and remember the times we had ripping on that very dirty mother fucker, and laugh. Once everything dies down again, the cycle is repeated with the coming, or, as is allegedly often the case for this particular site, the return, of a/the troll.
