This does not work. Just to prove it, I put the situation to the test.
Turned off home sharing on the ATV for a proper simulation.
Used a ProxySTA to connect ethernet bridge.
Power-Cycled ATV, and got main menu.
Guess what?.... no way to adjust anything because...... HOME SHARING IS NOT TURNED ON!
You need home sharing turned on so...... the question is... if you already have home sharing turned on, what on earth is the point of needing Ethernet in the first place?
I suspect the author... trying to do troubleshooting on his own jumped to the wrong conclusion, and somehow thought he had discovered a simple TRICK that every other engineer at Apple (& user) seems to have failed to notice.