> Opera, Safari, Chrome and Firefox all run on a variety of OSs, which is exactly what a web browser should do.

What do you mean? The web itself should be accessible on a variety of platforms. It doesn't matter in the least if every platform has its own unique browser so long as they are all decently compatible. That's why we have open standards.

If I'm running Windows, why should I care that the browser doesn't work on Linux? How does that have anything to do with it being "modern"?

Your last sentence makes no sense. Instead of using IE9 to view Hacker News, I should go find a native app? Huh?

(I actually use Chrome and have no love for IE, but arguments like this are just silly.)