PC gaming for FPS is still big it's just not as visible as it's centred outside US where that demographic has shifted massively to consoles or around digital sales a'la Steam. As an aside you can normally figure a region where 360 is much weaker is one where PC will remain dominant for FPS - for example in Germany you'll still regularly see PC FPS titles outsell console FPS titles.
I still find that, although PC FPS online has its fair share of annoying lone wolves, cheaters, etc, you still find better teamwork and play on PC vs consoles for this type of title.
Given the nature of the challenge was aimed firmly at teamwork vs focusing on your own character leveling or K/D ratio I'm not surprised at the result.
Try to be reasonable... its easier than you think...
