Taking a side isn't always the best choice. For instance, when it comes to judges, they cannot take sides; they have to be neutral and look at the evidence before convicting anyone.
When it comes to gaming, picking a side and sticking with just one console doesn't make one more knowledgeable on gaming consoles in general, and in fact makes one more closed-minded. A neutral stand is better because, without an obsession over one console, the gamer can more fairly judge the games.
From what I understand, professional gamers tend to be neutral as well, and generally look down upon obsessive fanboys that stick to one console and bash the others.