Xbox360 is losing ground while the PS3 is rising.
People supporting the Xbox360 are frustrated because of this trend that is all.
...
(if sales change then people mood will follow ...)
Also, most of the MS supporters were Sony supporters some years ago. So they feel guilty to have switch to the other side particularly if this side (Xbox) is falling or, at least, not succeeding enought ... (not enought people want the console in PAL+Japan, check the sales).
Time to Work !