It complained that this use of the word "polyfill" was "stupid" because it just referred to the code sample I copied in my comment, and that older programmers would recognize the word as referring to polygon filling operations.

Basically, it sounded like the comment author went in expecting an article about rasterization and was upset to find that web developers used the word for something else. Which I'll admit I've also done before on other topics, but you can't begrudge other fields their jargon.