I would argue it's all a bit of confirmation bias, or self-fulfilling prophecy, or anything of the sort. Whatever you want to seek out, you'll probably find it anywhere you look. But players think/expect they ought to go to a particular server/data center for a particular thing, and, what do you know, they find the thing they were looking for. That doesn't mean they wouldn't have found it on any other server/data center. They're all comprised of large groups of people with varied interests.