I wonder if it is something firefox and chrome devs need to look at because if it is accessing the audio device surely it should be notified to the user.
I can only assume that there are legitimate reasons for this as well, e.g. websites preparing/maintaining audio context for lower latency when they intermittently play audio etc.
Every time an article like this comes out, people wonder about aliexpress instead of why their browser allows this in the first place.