I'm not sure I follow that analogy, if you get a ride to a hospital you don't expect it to lock off all other destinations. What happens in the hospital is irrelevant.
From reading the article, this is more like if you walk into a hotel and they burn down your house so you have no choice but to stay. I suppose in theory you could argue in very bad faith that this is a problem with the house since it's the house that burned, but in reality the problem is the fact they're the ones who started the fire.
Username and display name can be set independently, you should have a "Display name" field in settings. Their non-unique display name is "max" and their unique username is "@[email protected]". If you check their profile you should see both.
If you don't set a display name it will be the same as your username, if you set display name to the same as username (like I have) it'll show your username without the instance even to people on other instances.