Check again guys, its been removed from the list.
Updated poll or something else?
I'm guessing that it updates on a regular basis based on how people on the site are voting. At the top it says, "As voted on by ThemeParkInsider.com's readers." And then at the bottom is "You can find other attractions to rate and review on our Disney, Universal, and other theme parks' listing pages."
So I'm guessing that as people vote, rate, and review that the top 50 updates based on that. So if a bunch of people went and flooded a certain attraction with positive ratings, it would move it up in the rankings. That would make sense, and could be a way to try to keep the list as active and current as possible.