Things that are obvious to you and I might not be obvious to every reader. Remember that the BBC has a broad demographic, including kids and people of varying educational backgrounds. Their content is intentionally written to be accessible rather than placing assumptions on the readers prior knowledge.

Do you think that many readers patient and interested enough to reach this point in the article lack knowledge that there was no electricity in the ancient times?

Many? No.

Some? Given the laws of probability and the points I raised in my previous post, yes it is possible.

If you take issue with BBC's mission (https://www.bbc.com/aboutthebbc/governance/mission) then I suggest you research the same content from different sources rather than moaning about it on HN because for a great deal of people in the world (and especially in the UK) the BBC is a great source of accessible content. And frankly, it's much easier to criticise someone else's writing than it is to publish something that is both informative and accessible.

I am not hating on BBC just this specific article of this specific author.

I've seen people honestly believe than the world was black and white right to the middle of 20 century. You're way too optimistic.

I don't think those people read those kinds of articles. Or read anything beyond TV guide.

Cinematic tropes of ancient times often show thing slike slaves operating giant fans, either hand held or operated by levels. Since slavery is no longer acceptable it's not surprising that people might be defaulting to the assumption that cooling requires mechanical movement which requires energy, whereas this form of cooling is wholly passive in nature.

The baghdad battery is ~2000 years old, so it might be important to point this out.

It's strongly disputed that this device was built to produce electricity.

Gotta hit those SEO text length targets with as little effort as possible.