Agreed. If you want to prove to yourself that this vulnerability is real, consider that you can replicate the hypothesized malicious device you describe by taking a WiFi Duck https://wifiduck.com/ and combining it with a regular lightning-to-HDMI adapter by plugging the WiFi Duck into the extra lightning port on the HDMI adapter. All that would be needed to use this attack on an unsuspecting victim would be to combine the WiFi Duck and the HDMI adapter functionality into a small enough circuit board to fit into the Apple-style white enclosure.