Touching the ball is irrelevant. Attwell was supposed to apply the criteria for an opponent interfering with play as stated in the laws. As you can see Rashford was clearly interfering with play because he breached at least three of the guidelines listed; namely preventing an opponent from playing the ball; obstructing an opponent's line of vision; making an obvious action which impacts on the ability of an opponent to play the ball. Rashford ran towards the ball, shielded it, and obstructed Akanji and Ederson's vision.
IFAB Laws of the Game
www.thefa.com
The decision by Attwell wasn't a mistake. It was a suspicious decision. Remember the linesman called it correctly but was overruled by Attwell. He didn't even check the video. The rules are clear.