TheNoobHolocaust on 27 June 2013
I'd say it's because Sony fans are more passionate about their games. Sony fans weren't dominant in the early days of the PS3 because they didn't have anything to defend with Sony, as they themselves felt cheated by Sony.
I suspect that is why during the DRM week MS fans weren't willing to jump to defend MS, because they didn't feel that they were being treated fairly. When given a reason to defend these companies in the form of great games and policies fans tend to feel an obligation to defend those companies.
The simple answer to why Sony fans dominate the internet is that for the majority of the generation Sony fans have felt that Sony had their best interests in mind and they felt obligated to defend them.
