I think Ventura felt that Giambi was a bigger risk at that moment to beat us than somebody who has better numbers as a hitter following him. It is easy to look at numbers and know what the right call should be. For all we know pitching to Giambi would have cost us the game... he's done it before, and not just as a young man.
Of course, a computer could manage the team better in theory but I prefer a human who can think and be creative and weigh intangibles. Of course, if they want to computerize the strike zone I would have no argument with that. No creative thinking required there.