WHAT!? I'm so confused, lol! Why can't you just play 2 people online without doing all this!?
When you're in a party of 2 including yourself and try to find a game, the match simply wont start without finding a 3rd or even a 4th player.
Doing this 'trick' prevents other people in public to join your game because they wont have time to join your game when the countdown is around 1 second which is when you sign out of the 2nd controllers.