So many website break completely with JS disabled and you end up having to enable it half the time anyway.

IMO web browser have been enabling all sorts of obnoxious behavior since before JS. One of my all time favorites were the sites that opened pop-ups in a loop faster than you could close them while an audio clip of a guy yelling "Hey everyone! I'm looking at gay porn!" You had to hit reset. Fuck the Web.

They probe all audio devices, including microphones, which probably temporarily switches Bluetooth devices into HPF mode due to how Bluetooth duplex audio works.

I'd argue it's "silent" though: aliexpress wakes up my audio card if nothing plays, which results in a very faint "pop" sound every time I open the tab.

It's been this way for ~3+ years at least.

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.

The script generates a known waveform, it is passed through the browser's audio implementation and then the script analyses the result after. Based on your devices settings and hardware the output will be different, e.g. a PC with analog output might have 44KHz audio output bandwidth, but a bluetooth headset might have a lower, different audio bandwidth. That is a datapoint that can be used in device fingerprinting alongside screen and viewport dimensions, device pixel ratio, browser plugins, etc.