As Bill Barnwell of Grantland is fond of saying, in the first half, your only goal is to maximize your expected points. You don't know exactly how many points you're going to need in the game until the end.
His phrase doesn't really have any impact on the argument being made here unless you really dissect the relative importance of offense versus defense in the game, which requires a lot more evidence to make a case one way or the other.
To illustrate: in an infinitely long game, you always pick whatever gives you the highest expected value. In a game with one play left, you always pick the play with the highest probability to put you over the amount of points the opponent has, even if has a lower expected value than other plays.
The quote is saying that the first half is more similar to playing an infinitely long game than a game with one play left.