The other end of HDMI would need to offer a network connection for that to be real. Also its so poorly supported it might as well not be a thing. Noone implements it and it isn't just a "there's Ethernet wires in the HDMI cable", it uses some multi-purpose pins that both ends have to agree to use.

If anyone ever actually builds a TV that supports it* then the list of things one must actively disable will have grown all the way to two. Again, not hidden spy equipment; no reason to wonder whether your TV is secretly communicating with someone.

* https://apple.stackexchange.com/questions/325215/appletv-eth...