With a few exceptions such as myself, most players who come here are the type to meet good players online and thereafter party up (and also improve), so a high KD isn't *that* surprising. There are plenty who exaggerate, however.
On a related note, getting good stats really isn't that hard if you party up with Demolition spawn trappers. I've seen some absolutely horrible players with high KDs before.
Because the people here tend to be better than your average player. If you're the type of person who seeks out to discuss the game, you're going to learn things that others won't.
Another thing to keep in mind. There are probably thousands of people with 2+ KDs. Considering that Gamefaqs is such a relatively small part of that, you're going to find a higher concentration of those better KDs here.
Of course, some people are just flat out lying or they camp like it's their job. But for the most part, you're going to find more players with good stats on forums than you will otherwise. --- "It's like people using the internet have never heard of the internet." - SadHillShowdown Gamefaqs member
On top of what everyone has already posted, a lot of people here reset their stats so they have higher than usual spms and kds
Before I reset my stats, I had a 1.39 KD and around a 350 SPM since I played a lot of TDM. I have played almost nothing but Kill Confirmed since I reset my stats and my SPM reflects that. It's 431 overall, 433 in Kill Confirmed. My KD is nothing special at 1.53.