I think it doesn't have as much to do with HN as it does with the startup scene itself. A few years ago before the mobile apps, there were fewer people in the startup scene, and those that were there had a more communal sense. Since we are now quite common, there is a lot more competition out there, which probably fuels some of the frustration directed at you.

personally, I wouldn't tear anyone's work down, but I can see why some people would, given how crowded it is now.