I like this analysis, though I personally believe the current culture and prevalent behavior that you describe as "toxic" has more to do with anonymity in and of itself, as well as how it's moderated, rather than how the site functions. Some of the slower boards, and spinoff sites have a vastly different culture as a result of this, and the contrast is sometimes jarring.
From the few comments I've read by the original creator of the site, Moot, he described the function of the site as a "survival of the fittest", where the best and most interesting ideas would stick around. He said this in the context of memes, as when the site used to be known for those, but I believe it holds some value, as people generally don't forget things even after the thread's gone, and it gets brought up again, or it gets saved in some image folder. Unfortunately, controversial content will always get the most engagement on any platform, be it through upvotes, bumps, or the sheer number of posts. You can see that on sites like this just as well, but also on the news on TV. Bad news reaches far and wide, that's just human behavior. Online this mostly becomes a question of how it's moderated and if you can even moderate it after a certain point. I believe Moot eventually gave up on this after events like Chanology and gamergate were really taxing on him, and I'm not sure the new site's moderator is very invested in regards to this.
It's interesting to note, that instigating raids is a bannable offense (rule 4), and I've witnessed many posts calling for this get deleted. But often, especially on this site, this cannot be contained once the cat's out of the bag, as just hopping on the next IP address is enough to continue posting, and people quickly move to other means of communication.