Short passive-aggressive version: Because I’m a pretentious twerp.
Long, less passive-aggressive version: Because it’s irrelevant. The gear a photographer use to capture an image is essentially irrelevant, what matters is the result. You can use a really cheap camera and as long as you get what you want – more power to you. Expensive and high-end gear does not take a picture, the photographer does. Expensive and high-end gear helps the photographer but it cannot substitute it. Also, look at the Lomography movement; they use some truly crappy gear but that’s all a part of it. They want the lo-fi look.
I love talking gear, I really do. I will happily discuss gear with anyone else but this is not a site to discuss gear – this is where I show the moments that I’m proud to have captured. The gear used does not matter. This is also why I’ve started taping over the logos of my gear, since I don’t want the logo to distract anyone. I want people to think in the generic term “camera” when they see it, rather than (no pun intended) focusing on what brand of gear it is.
It doesn’t matter what gear you use as long as it fits what you need it to do. If it’s not doing the trick, change it to something else.