From my personal experience, the "fanboys" as they are called are a product of this console generation. I remember with the Sega and SNES we never argued about which system was better, all we cared about were the games. I remember people coming to my house to play my Genesis and going to other peoples houses to play NES or SNES. Sure we all had our favorite system but it never got to the trash talking and other ridiculous shit that happens today.
Even when the PS2 and Xbox were on the scene it seemed like more of a friendly rivalry between people rather than a friendship destroying choice by choosing the opposition to the console of your choice. I never had remarks made about me because I chose a PS2 over an Xbox but nowadays people have no problem talking about you, your wife, dog and mother simply because you chose a different console.
Of course I wasn't on gaming forums when I had my PS2 or Xbox so it may have been just as rampant then as it is now, but from my personal experience the fanboy attitude has started this generation.
I agree tenfold. I had both a SNES and Sega, and even though I preferred SNES personally, Sega was still damn good. I only recently saw any kind of back and forth, when I bought my PS3 for xmas 2 years ago, and my bro in law called me a "pussy" for not getting an xbox and playing Halo... huh? I personally hate the layout for Xbox controllers, and I've always loved the PS version of controller.