Blizzard....
Not every Nintendo or Sony console owner is necessary a fan of said company. Purchasing a console is a one time thing and doesn't necessary mean you are happy with the product afterwards or become a fan of said company afterwards.( that would be like saying that once you had a mocha at Starbuck and now you are de facto a huge Starbuck fan...)
Blizzard has 11.5 million of fans at the minimum...( when you return to the same thing every day and pay for it every month I think you qualify as a fan :p)