And by that definition the Bolt record is not a data-point, it's a global property of the distribution, namely the minimum value.
In his main argument though (and your example here), we just have a single value, and no information at all about the distribution, we don't even know if n>1. In such cases we can hardly say anything at all.
So in order to be able to infer something from the single datapoint, we need to make assumptions about the distribution of the values. The problem is that all the interesting conclusions we can draw come from those assumptions, not from the single value itself.
To tie it back to Usain Bolt. If you only know his time on 100m, that means nothing. We can of course posit that he's the fastest in the world, and from that we can draw conclusions such as "everyone else is slower", or (somewhat less trivially) that "the average time is above 9.58 s".
But we could equally well posit that he is the slowest in the world or that everyone is equally fast, which would lead to completely different conclusions.
So we clearly see that all the interesting information comes from the distribution, which sort of makes his arguments pointless.
And if I then told you one example alien covered 100m in 9.58 seconds would you not change your estimate at all from learning that information? You wouldn’t assign less probability to nuclear powered teleporting aliens or crawling vine plant aliens or insect sized slug aliens because “you can’t say anything without knowing the distribution”?
No that would be silly; you would put a lot more weight on times around 9.58 seconds, because that tells you something.
Saying “it doesn’t tell you much” is right but it’s told you something, there is non-zero amounts of information there.
From pure statistical reasoning, or even taking into account basic physics (e.g. speed < c) and biology (e.g. speed > 0, almost certainly speed << c), you can't conclude anything about the average speed of an alien species by finding out that one individual can run as fast as Usain Bolt.
Maybe not much more. But definitely more. And not with 100% confidence, we can't conclude anything. But there is information there, and we would be daft to ignore it completely because it isn't conclusive. We should adjust our predictions.
> "you can't conclude anything about the average speed of an alien species by finding out that one individual can run as fast as Usain Bolt."
If you know that a sloth takes 6min40s to cover 100 meters, a giant ant takes 1min40s to do it, and you run it in 30 seconds and a cheetah can do it in 5.1seconds. I say "I'm thinking of a creature, what is it?" your answer has to be "I don't know". If I say "an example of the creatures I'm thinking of takes 9.58 seconds" you ought to be thinking "slow cheetah or fast human" not "could be a sloth because ackchyewally the distribution of sloth speeds could be very wide so we don't know".
You could assume the individual was the fastest of their species, but why would they be? You could assume the individual was noteably slow, a famous creature to be laughed at. With no way to know which is the case, you may as well assume the creature is a typical example - not because you know they are, but because if they aren't you have no way to know which way they aren't.
Before we knew nothing, now we have more information than nothing. We ought to update our predictions based on this information, even if it's not much information and we can't know for sure. We ought to think the alien is less likely to be an immobile plant or silicon intelligence, less likely to typically move at the speed of a sloth. Not impossible, but this isn't meant to be a trick question where we get a deliberately wildly misleading time. 9.58 seconds is more like (cheetah, human, giant ant, jellyfish) than it is like (panda, mushroom, saltwater snail, sentient light beams). And yes, there might be nothing like those creatures at all, but "we could be wrong" is no reason not to adjust our best available guess.
[1] https://www.newscientist.com/article/2220211-desert-ant-runs...
From pure statistical inference, you know precisely 1 more thing than nothing: an individual of the species can run 100m in 9.58s.
Now, adding other kinds of information and reasonable assumption from physics and biology, we can conclude more than that 1 thing, as you say. It's unclear exactly how much those would apply to alien biology, but they might.
That is the absurd case, one piece of data has total information in it. Accept that, and you can then see that a less extreme datapoint can have less extreme amounts of information in it, and can be used to make less confident predictions - but still more confident than guesswork.
Really the only point is, if I picked a random person and asked you to bet $1 whether they were slower than Usain Bolt, would you say “ok” or would you say “I can’t infer ANYTHING from only ONE data point”?
If you can infer something from only one datapoint, you can infer something about aliens with better than guesswork confidence using humans as one data point.