I think people are reading your comment as "they need to know these things, therefore they are elite" - but I think you rather meant "it's not about being elite, just that they have to know XYZ so they are more likely to know W".

yes, exactly. But, the reality is that top HFT firms at least try to hire 10x programmers. So call them elite or not, but the calibre is high

Eh, I don't think that follows. Top firms in many sectors try to hire elite programmers. Do they succeed? Further, how much of the industry is made up of hires of top firms?

I have no particular position on the elite status of those working in HFT. Certainly there are some smart people there, but I don't know how to generalize. I don't have anything like a representative sample of either HFT or programming more broadly to compare, despite having worked in HFT and out of it.

Top firms in HFT try to hire elite programmers and they tend to succeed. Think of it this way, if you are hiring hundreds or thousands of people a year, then it would be extremely difficult to make sure most of them are elite. Plus, chances are your projects don't require it anyway. Many projects need good talent, but not elite. But if you are hiring 1-20 people per year, then making sure that at least some of them are elite is not terribly difficult

I can see the reasoning, I've just little confidence other dynamics don't dominate. I'm not saying I'm confident they do; and even if they do it's certainly possible for them to push the matter in either direction. But I'm saying that I don't know, that nothing you've said is anything I haven't considered, and that it's likely you also know less than you seem to think. And again, I'm saying that as someone who has worked in HFT.