The question if he could have saved it if not for the player in the offside position. If the keeper didn't move because he was there, then that is interfering. He is not blocking his eyes when the shot is taken, and that is always interference yet he is in the offside position on the line where keeper needed to move to make a save, he is blocking the path to a possible save. If your claim is that De Gea wouldn't have made that save, then that is the discussion. I've known De Gea to make incredible reaction saves, so I wouldn't put it past him, but whether or not he is a pussy shouldn't be a deciding factor during a VAR process.