As I remember it, Williams came flying through the line, and his flailing hand happened to hook inside Boller’s helmet and pull it. Williams was penalized 15 yards for the play, as he should’ve been, but it was obvious that the whole thing was unintentional.
Obvious to everyone except the NFL don’t-touch-the-quarterback police who clearly read malicious intent into Williams’ actions, hence the fine.
If Rodney Harrison were here, he would tell the NFL gestapo to take off their skirts. And get their eyes checked.