The problem with that analysis is that you're expecting quality conversation from threads with 1000+ comments in which comment threads themselves are largely insulated from each other. There are very rarely reference to another comment thread within the same post, which leads to isolation and localized groupthink.

Generally speaking, threads of that size imply that they are posted on a very popular public subreddit, which requires no special qualifications to post in. Invariably this leads to at least _some_ comment threads being low quality.

I would not be surprised if the majority of such highly commented posts contained isolated comment threads with racist remarks.