Genuine question: at what age is Olber's Paradox explored in high school physics these days? (It was part of my A-level physics curriculum in the UK, age 17, circa 1981 ... I'm finding it rather odd that it was unfamiliar to this journalist!)
I suspect this is because the US high school education system has a fairly standardized, one-size-fits-all curriculum. There are some allowances and exceptions, of course. But, for the most part, everyone is going to be covering roughly the same material. And astronomy isn't deemed as necessary, for the beginner, as some other rudiments of physics. College, on the other hand, offers more opportunity for individual choice in one's curriculum.
Astrophysics is generally popular among students, but afaict it hasn't been included basically because the physicists consider the above three courses to be higher priority.
To the best of my knowledge, and in general, it isn't.
> I'm finding it rather odd that it was unfamiliar to this journalist!
It wasn't. It was unfamiliar to his daughter. He posted it because he's aware that the public is generally unaware of it, not that he is.
(I'm only partly joking. My high school biology class had a chapter on evolution. The teacher said "I have to teach this but I won't be testing you on it. Read the chapter and let yourselves out when the bell rings." He then left the room.)
That experience is heavily colored by watching University Challenge and Mastermind, but I do not think that makes a difference when comparing the top levels (which, I guess, we are; those not in the top levels at A level physics will not remember hearing about Olbert's paradox)
Most people, even the best students (I was one of those), did not.
Disgusting, isn't it?
Typically it would be discussed in the context of cosmology; if they don't cover cosmology at all that's unfortunate, but not mentioning this very specific footnote to it would be understandable. And even if they do plan on covering it, I'd be a little surprised if it was listed on the syllabus.