I think some HN commenters are having issue with how the map legend is labeled. The key labels darker colors as 'more fans' when they mean 'larger fraction of fans'.
I think NYT chose the right methodology, they just got lazy with the labeling.
I think you don't understand what that word 'popularity' means...
I guess you don't believe something can be popular in a small community.
It can be, that doesn't make it popular in general. Duck Dynasty has zero viewers in my living room, does that make it an unpopular show? Having a small number of absolute fans in isolated clumps does not make something popular unless you specifically scope the definition to make it appear so.