I didn't downvote it but I know why it's downvoted.
The downvotee could clearly imagine this being unintuitive if he were inclined to be so creative. The entire comment evals to "I inherently grasped statistical thinking from birth, what's wrong with you that you didn't?"
To borrow from a Hacker School post a long time ago: it's feigning surprise[0] at the ignorance of others. If you're on HN you probably work in an environment where learning is a non-optional part of your every day. Getting to the point where not knowing things isn't a blow to your self-esteem can be a pretty big professional hurdle for people.
Unless the downvotee was born with an inherently sound understanding of statistical thinking and also has some trouble empathizing with other humans then his comment was just going out of his way to tell a fellow human that their moment of learning and realization was remedial.
Edit: After explaining it and rereading the downvotee I decided to downvote as well. The clincher was following up with the implication that the original poster was not only remedial but poorly educated.
The hover text is especially applicable: "Saying 'what kind of an idiot doesn't know about the Yellowstone supervolcano' is so much more boring than telling someone about the Yellowstone supervolcano for the first time."
>> Unless the downvotee was born with an inherently sound understanding
This part? I meant "was born" as made the jump from being a fetus to being a baby, not "borne" in the sense of being carried, although I guess that works in a bit more poetic sense.
(Also thanks for the comment either way, always happy for feedback and corrections)
Whoops, did you edit that? I could swear I read "the downvote" rather than "downvotee", but then it doesn't make sense in context anyway. Brain fart, I guess, sorry.
While total ignorance of statistics might lead you to expect suicide rates to be wildly unpredictable, and knowing a bit of statistics might make it obvious that they shouldn't be, knowing more statistics should make it not-obvious again.
So, from a position of total ignorance you might say: suicide rates are the result of lots of individual freely made decisions, and should therefore be completely unpredictable.
Then if you know a bit of statistics you might say: no, the population's suicide rate is the average of the individuals' suicide rates, and averaging things reduces their variance so we should expect it to be quite predictable.
But if you know a little more statistics, a few other things will occur to you. The first is a red herring: averaging things only reduces their variance when the variance is finite. Standard counterexample: mount a gun or laser or something on a swivel mount with a 180-degree range near an infinitely long wall. Point it at a random angle and see where it hits the wall. This gives you a position with the so-called Cauchy distribution, and the average of a million of these has the exact same distribution as a single one. (That doesn't mean you can't extract information from having lots of samples; e.g., the median is nice and informative. It just means that taking means isn't the way to do it.)
Why is that a red herring? Because an individual's suicide-or-not during a given year can only take the values 0 and 1, and therefore its variance can't be larger than 1/4 (and in particular can't be infinite). So averaging together lots of these should give you something well-behaved, right?
Not so fast. Those individual suicide-or-not random variables may be correlated (e.g., when Goethe published his gloomy book "The sorrows of young Werther", whose protagonist -- SPOILER WARNING -- kills himself at the end, a wave of copycat suicides swept across Europe). And they may depend on something that varies with time (the same example will do nicely, but you might also consider economic conditions, weather, polluted water supplies, etc.), and there's no reason why that something (or those somethings) shouldn't swing around wildly.
So no, it isn't altogether obvious to anyone who knows some statistics. It shouldn't be a big surprise if in fact suicide rates are pretty well behaved, but I think if you think it's obvious then you're not thinking hard enough.
The default psychological view (if you can call it that) in 1830 was Romantic Individualism.
The default psychological view in 2016 is that objective statistical trends are the rule across populations, not the exception.
There can be arguments about which statistics apply, and whether or not they're accurate and not measured poorly, or impossible to replicate, or even deliberately dishonest and politically motivated.
But there's no argument that in principle it's perfectly scientific to use statistics to identify and measure behavioural trends.
The shock in 1830 was discovering the latter fact. The idea that something personal like suicide might fit a measurable statistical trend was completely novel - perhaps because it directly challenged beliefs about heroic personal self-determination.
The fine details of the distributions don't matter. The fact that statistics can be used at all shocked people in a way that it doesn't now.
