Rashford was offside,Fernandes wasn't.
Rashford never touched the ball so the rules don't cover interfering with play in the manner in which you claim.He didn't ACTIVELY obstruct Akanji,who waas 2 yards behind and never getting back,neither did he obstruct Walker or Ederson.
Rashfords presence most definitely affected the decisions of the our players,but seemingly that isn't against the rules and is the reason the officials came to their decision.
And just in case you are confused.....once again,i agree that it is bollocks and the game has gone if that is deemed a legitimate goal.