Like him indicating that since he was only eight years old when Ayers did his bombings, that he should not be viewed negatively for his association with Ayers today.
But Obama was not eight years old when he took money from Ayers for his campaign, or when he sat on the board of trustees with Ayers, or when he went to Ayers house for a campaign meeting, or when his (Bama's) campaign indicated that he and Ayers were on a "friendly" relationship basis. All of this occurred after Ayers made it apparent that he was not repentant for his terrorist bombings and only wished he had done more.