Why does Mastodon ask which server I am on?

Mastodon is not one website; every reader's account lives on a server of their own. The button asks each time, with the server the reader gave last time already in the box, so sharing again is one press of OK and a wrong answer can always be changed. Up to 1.4.31 the box came filled in with "mastodon.social", and pressing OK saved it for good; a reader on another server could then never share there without clearing the site's data in their browser. A typing mistake is now answered with "That does not look like a server address" and the question again, where it used to do nothing. There used to be a setting to switch the question off, but without it the button had nowhere to send the share and did nothing, so the setting is gone.