Probably because it would give more ammo to people like YOU to make new accusations about him. As for pardons, IIRC those remove ALL RECORDS of a conviction. Cleans the slate, like it never happened. Which is exactly what a substantial number of them deserve. Sure, if they did material damage, assaulted cops, and the like, no pardon. But MOST of those 700+ were guilty of TRESPASSING. If it were my choice, they'd be pardoned and the Feds would be writing them a VERY GENEROUS CHECK for every day they stayed in a cell.