I would consider all relevant points, that the article may touch, to see where deltachat may suffer a neglect. Even beyond their literal understanding.
- kind support for email replies to “unsubscribe” or “leave” (mailto link in footer and appropriate unsubscribe header in group emails)
- ask to “unsubscribe” from groups when uninstalling deltachat
- verbosity of administrative messages
- missing BCC group / news feed messaging (see post before yours)
- lost protection against spam disturbances (receiving messages from unknown contacts)
- email/message reachability / visibility