He claims he is doing it because he thinks it is best for the girls. I see no reason to impugn his motives. You said he was doing it because Merck gave him money. If you had just said Merck gave him money, you'd have an argument (although the implication would be there). But you said he was acting NOT out of a well-meaning but ignorant desire to help kids, but cynically saying so because he wanted campaign contributions.
That is a decision for me, my wife to make with advice from a PRACTICING pediatrician, not a governor beholden to a drug manufacturer.
Do you ever question a politicians motives? There are two things that motivate most politcians, money (for reelection) and votes. The former helps procure the latter.
If he thinks it is best for girls, why not have the state strongly urge parents to get this for their children? TV ads, magazine ads, radio ads etc.? Why not do it through the normal legislation process? The answer is because those methods would take time (a loss for the manufacturer), and it may not pass (a huge loss for the manufacturer).