Do traditional American sports have black and white laws, with no grey areas?
Yes, many of them do.
NFL especially has Rules that nail stuff down to the nth degree. This is not surpising given that there are SEVEN officials (referee, umpire, head linesman, line judge, field judge, side judge, and back judge). The also have a replay official who has access to up to 20 different camera angles. No room for grey areas; they would be a veritable minefield.
For example, out of bounds rules. If you think ours are confusing, read this...
If any part of a player's body or clothing touches the white border around the field perimeter, that player is out of bounds.
If the player is carrying the ball, then the ball is dead at that spot.
A player who steps out of bounds cannot be the first player to touch a thrown or kicked ball.
If the ball touches another player first--such as a tipped pass--then the player returning from out of bounds can catch it
Any player who goes out of bounds must attempt to get back on the field as soon as possible.
If he doesn't, he can be flagged for a 15-yard unsportsmanlike conduct penalty.
If a fumbled ball touches the white border it is dead, and the team that fumbled the ball retains possession at the spot where the fumble occurred--not where the ball went out of bounds.
if a fumbled ball rolls or bounces into the defensive team's end zone and goes out of bounds from there, then it's a touchback, and the defensive team gets possession of the ball at its own 20-yard line.
If an offensive player fumbles the ball in his own end zone and it bounces out of bounds, it's a safety, which is 2 points for the defense.
The game clock stops when a ball carrier steps out of bounds.
For most of the game, the clock restarts when the officials spot the ball for the next play from scrimmage and the referee signals the clock operator to wind the clock, except, during the last two minutes of the first half and the last five minutes of the fourth quarter, the clock starts only when the ball is snapped for the next play.
A receiver catching the ball at the sidelines must get both feet in bounds and maintain control of the ball for the catch to be legal.