It's the website.

The title of the article literally mentions "WebAudio", and the first paragraph states that the author is using a PC. The second paragraph mentions Chrome and Firefox.

Apple and the App Store have zero involvement here.

This is a huge stretch, but if this problem exists in not only the PC versions of Chrome/Firefox but also the Android/iOS versions, then theoretically the app store reviewers could flag the browsers for facilitating this behavior against app store guidelines. In practice, apps of such caliber as popular browsers might be a bit above such reviewers' pay grade, so to speak.

> This is a huge stretch

This is nonsense. Safari also supports Web Audio. Safari does not, however, support Microsoft Windows, which is why the article author didn't mention it.

Moreover, all web browsers on iOS have to use Apple WebKit, so Web Audio support is not actually the fault of the non-Apple browser vendors.