Perhaps there could have been a legitimate point about traffic deaths, but whatever substance this comment might have had is more than squandered by that acerbic swipe.
I feel ashamed of Hacker News to see a thread about someone's death abused like that.
I agree with your sentiment. That said, this is an amazing community, no reason to feel ashamed of HN because of the ignorance of a few comments. That those comments almost always get downvoted to oblivion, reveals the true character of HN.
I wonder if HN would benefit from adding an autoflag to "'murica." I've very rarely seen it used for anything other than particularly ignorant insults or otherwise negative value comments.
Considering the role of environment on intelligence, I would consider that to be extremely unlikely. If you restricted your statement to "other developed nations", that might be a bit more plausible.
