It has nothing to do with PS3 fans being more "hardcore", or any other kind of intrinsic difference between the fanbases. It might seem counterintuitive, but PS3 fans are the most vocal because their console is in last place. The feeling that their console deserves to be in first place - coupled with the reality that it is actually in last place - is what causes it. 360 fans don't have the same sense of entitlement, partly because Microsoft has never had a first-place console, and partly because they have the consolation of their console at least being in second place.
This is why you see several posters here with PS3 advertisements in their sig, but pretty much no one with 360 or Wii advertisements. It's why "buy a PS3" was a standard response to many threads completely unrelated to the PS3, to the point that it became ban-worthy. Meanwhile, "buy a 360" was only occasionally seen in such threads, and "buy a Wii" was almost never seen. Nintendo fans already have their console solidly in first place; they have no need to shill for Nintendo in order to see their console "win".
If you've been reading gaming forums long enough, you've seen this phenomenon in action before. Last generation it was the GameCube fans who were the most vocal; Xbox fans were next, and PS2 fans just ignored the console wars. As far as PS2 fans were concerned, the "war" was over before it started - Sony won, and the other two consoles were irrelevant. Nintendo fans felt the GCN corrected the N64's mistakes - such as lack of an optical drive - and therefore Nintendo deserved to reclaim its rightful crown.
