Nah you're just expecting Rashford to be some sort of footballing savant who can predict where the opponent is going to place his leg. There is a big difference in knowing there's an opposition player in your vacinity then knowing he's going to put his leg where you're going to put yours - you do know the bloke put his foot in right? He wasn't just stood still.
If the bloke was just stood still and Rashford planted his leg into him then yeah, you'd have a point - he probably should open his eyes - but considering he had turned around to shield the ball and the player was moving in simultaenously, it's absolutely ridiculous for you to suggest he should have known the opposition leg is going to be there.
Anyone who has played football before has done a similar movement with opposition players around you.
This is getting ridiculous. Rashford sees him coming, he misjudges the amount of time he has left before the opponent arrives, attempts a last second shield and hits the player in red worthy manner on shin height. Not the first time it happened, won't be the last time and it is a red now and then. It is actually quite easy, he tried to put his foot where somebody else already was in an active and conscious way, not by tumbling or falling or by any other way in which you could void him of any blame. As I said, there would be zero discussion about whether or not the red was justified if it happened the other way round.
And I've played enough football in my life and to a decent enough standard to know that this is bad awareness and timing by Rashford. It is clumsy and stupid, nothing more to it.