It seems to me that it is not how many people hate the Yankees, but how many Yankee fans hate the Yankees.
The formula helps determine whether consumers have positive, negative or neutral reactions to brands in their online messages.
It seems stupid, but I read this as how Astros fans react to online messages from the Astros. (Astros can be changed with any other team.) But, if this is right, then I don't see how the Pirates aren't the most hated team.