My problem is not that it automatically redirects to example.com.
It's that visitor only see "example.com" because the www is hidden. When they later type in "example.com" in the address bar to revisit the website (because that's the address chrome shows them) they are just sent into the void with no idea what is happening.
They then go back to my website via some link that was sent them to find the correct url – but again see "example.com" in the address bar and tries to visit it again in a new window – but of course it doesn't work this time either.
The visitor is then thoroughly confused why my website only works when they visit it via a link, and not when they type in the url directly.
Most people (reasonably) assume the text in the address bar shows the correct address, since that's how it works in 99% of cases. URLs containing www are the only exception.
I just get annoyed at the address bar not showing the full address. Thankfully some Chromium derivatives have a toggle to get the full url to show, but only on desktop.
But I think it's equally important that the user can trust their browser to show them the correct URL for the website they are visiting, not a "best guess".
