Every. Body. I. Know. that has a pair of AirPods commiserate.

I can only assume they know but can't fix it.

In fact, why isn't there "adjust volume to surroundings" like there is for brightness? They should KNOW how loud is appropriate based on mic input.

Maybe it's for people who drop their earbuds? So it can be heard from a distance? That would certainly explain it...

A hack would be to put some foam or so inside to dampen the sound and then max out the volume. Then they physically cannot make loud sounds.

Clearly the problem is just with how your ears are constructed, or how you are using your ears. Apple only makes perfect products, after all.

Just to provide my own ancedata, I've been an AirPods users for a long time, and don't find the alert sounds particularly loud or annoying.

I think the volume of complaints and popularity of AirPods this speaks to wider variations in human hearing perception than one would expect. The main body of users have no problem, but enough people experience those sounds as painful to generate a volume complaints.

Conversely, it might just speak to the different kinds of music we listen to. "Dynamic range" is a pretty big phrase you'll hear in the mixing industry, and Airpods effectively have no way to determine how loud your music is before sending an audible notification. If you're listening to a song that's mixed at -12dbLUFS on Spotify or Apple Music, the alert will play at the exact same volume as it would when you're watching a Netflix show mixed at -25dbLUFS. The difference in sound is, quite literally, an order of magnitude apart, and could quite easily account for having such a loud and annoying sound blowing up your ears and ruining your listening experience.

Same when switching noise canceling - why so loud?

Your comment made me realise that I actually never switch with the pods button (rather on the display of my phone) because of the loud noise. I don't get why they have not fixed this after years of complains from users.

Doesn't it still make the noise when you use the onscreen switch?

Either way it's horrible, all of these noises seem to be at a fixed or separate volume level than the media volume (which actually is common for apple). Siri used to have a separate volume than media (still might?), and then you also have ringtone volume, and sound in settings barely even hints that all these separate volumes exist.