why you should always take the ball in the 2nd half

Of course, the ball is more important in the 2nd half.

But furthermore, at home, when the game starts that's when your crowd is the loudest. They're ready to go, the game is tied, they're ready to yell. By starting on defense you can encourage your crowd to start yelling. If you put your offense on the field first, you're telling your crowd to quiet down, potentially at risk of taking your crowd out of the game. Conversely, on the road, by starting on defense you can force the home crowd to quiet down.