`polonez` is a deformation from the actual name `polonaise` (cf https://www.reddit.com/r/BoneAppleTea/), it makes sense that they don't mention it since it's obviously not Polish of origin (why would Polish people call it Polish dance ?)

They do mention the original Polish dance chodzony, extensively

Currently it's mostly referred to as "polonez", with that exact spelling. It's one of those loan words that got it's spelling changed in Polish.

And yet, this is exactly how it's been called in Poland for years. [1] Unsurprisingly, you can find "polonez" on gov.pl too. [2]

"a deformation from the actual name" in this context is called a loanword.

Regardless of etymology, an article talking about a national treasure being put on UNESCO list absolutely should mention that, IMO. Can be next to "chodzony". No problem with that. Even better, TBH.

AP didn't write even "chodzony", btw. Only "the «walking dance»".

  [1] https://sjp.pwn.pl/sjp/polonez;2572042.html
  [2] https://www.gov.pl/web/kultura/wpis-poloneza--tradycyjnego-tanca-polskiego-na-liste-reprezentatywna-niematerialnego-dziedzictwa-kulturowego-ludzkosci