Sometimes on HN or forums people like to take the words we use to simplify and say "it doesn't really do that" then have some philosophical story behind it all, that is just too pedantic. Similar to how I saw a conversation here the other day saying that "homeless" isn't the correct term anymore for someone who is without a home.
Too pedantic IMO.
But for technical people, the "propagation" explanation is actively harmful, because they might actually need to understand the mechanism of caching in order to do their work properly. And any technical person should be able to quickly grasp the idea of cache expiration being the reason why different clients can still see the old value for a time.
I don't think pedantry comes into the equation for this at all.
Using the term propagate is fine, because what is it to propagate anyway? and because of that, the devils' in the detail after all. Of course in technical terms the way that the records propagate is via the updating of cached records. But that is the mechanism in which DNS propagates.
You said it yourself, it's a fine to non-technical users. But of course, one single word cannot encapsulate how something actually works at a technical level.
We're being pedantic about how the word applies to how DNS records work, but it is the best option. Given that the author couldn't suggest an alternative, I feel that we're being too technical and nerdy of the use of the word.
Heck, Rackspace, Cloudflare and ICANN all use the the term propagate. ICANN even use it in their functional requirements.