How do they dox their users in this case?

The only time I have tried it, this happened:

1) win file explorer, right-click file and choose Share with iCloud link (not at pc, am paraphrasing)

2) test link in private browser tab

3) see “this file shared by First Last”

My apologies if I am conflating the way this file was shared versus the way I had shared

Yeah, I’ve only ever shared with people who know my name anyway, but you’re right, that’s no good.

Don’t iCloud share with the internet, got it! Thanks.

They also dox your email address. Someone shared an iCloud album with wallpapers on Reddit once. When I viewed it on my iPhone, at the top, you can click to see who else is subscribed to that album. But you don't just see their full names. You also see their email address (iCloud, gmail etc) plus you can start FaceTime calls from there.

It's a very bad design.

Wow! I guess this is design when only thinking inside the walled garden? Even then...

Click the link, you'll see who shared it. They are suggesting that Apple should have an option to withhold that info.