Difficult? They are frickin' helpless target drones.
Karnak, you and Moot exaggerate wildly here.
Player for player, bouncing your average P-51 and kill it is FAR less difficult and dangerous than killing the V of bombers it is escorting in the game right now.
This is ESPECIALLY true if the fighter in question is bomb-laden...it either drops the bombs to have a prayer of having enough speed or maneuverability to defend itself (mission busted), or dies.
And historically, and in-game, killing a 4 engine heavy is more important strategically than shooting down a fighter. So yeah, more points for it I say.