Short answer, yes. Our DELETE methods for profiles and unsubscribing users from a list are reserved for the API. This prevents any deletion that could also accidentally happen from the UI. You’ll notice that recipient profiles cannot be deleted from the UI as well unless you make an API request to the /profiles endpoint.
I can understand perhaps deleting a user entirely - but the fact I can add a user to a list within the UI but not remove them from the list just seems like a missing component rather than a feature. A confirmation dialogue could resolve accidentally deleting the user from the list.
You’re not wrong about your first point @keeon - I’ve created a feature request for having deleting mechanisms in-app for profiles and lists.
For the second point, I think the delete function for audiences is a bit laggy but able to deleted if you try to delete a second time. Opened an investigation ticket for looking into it. Thanks for pointing that out!