How do I post articles and comments on Busy without being logged in?
You can't! But you can use Busy.org for viewing without logging in, that's the only point I make. Otherwise you have to accept it.
I should also say that using your posting key is more secure than you're master key (called the active key), so really at every level they seem to be following best practice here. If your posting key is compromised you can always regenerate it with your master key.
I can see how you or anyone could come to that conclusion, I don't debate that it should be clearer, I'm just trying to make it clear to you, here 🙂 The ticket has been accepted so looks like they will do something about it.