I suspect that it doesn't take much to get the ball rolling on a knock-down drag-out fight between fans and opponents of any Work X: all you need is for enough people to have heard of Work X, and then you wait for polarization. As long as the work is popular enough that most people have heard of it, everyone will take a side and defend it to an extreme degree in a shrill voice. Works that are just good tend to acquire fans more slowly - Shakespeare, George Orwell, and Bach, while widely known, could not really be described as "sweeping the globe" at this time - and so they rarely have the critical mass of people who are newly excited about them and want to talk about them with their friends in casual settings.

A good example of polarization is the Twilight series by Stephenie Meyer (a vampire romance quartet mostly aimed at teenage girls) - no one seems to be neutral. Everyone either adores it and can't say anything about it that isn't incoherent squealing over how much they want to romance this or that character, or heaps it with such derision that you'd think it had killed their cat. Some people have opinions on it without even having read the first book, let alone the whole series. (My full defense of Twilight against the common criticisms may be found here for interested parties; warning, spoilers for all four books.) Each side fuels the other - there's apparently a belief latent in these people that the more extreme one's expression of love or hate of Twilight, the more successful one will be in converting the heathens/rallying support/setting every copy in the world on fire/getting Stephenie Meyer to come to one's house in person and give one an advance copy of completed-only-with-one's-encouragement Midnight Sun/whatever.