It’s not disallowed because “de gea wouldn’t have got there” . That isn’t the rule, in fact I don’t see what relevance it has at all.
He’s sat in front of him directly on the ground, about 1 foot away and there’s a question whether or not he’s in his eye line? As in What? unless David De Gea’s eyesight works differently to normal people’s there is no way Sigurdsson was not in his view. Degea could not have judged the path of the ball without seeing Sigurdsson because the ball was on the ground along with Sigurdsson. Dunno why I’m surprised though, judging by the Everton fans at the game today, all the fake injustice with the booing of the ref at half time and full time, genuinely laughable. Can’t even tackle an Everton player clean without the weirdos at Goodison shouting for free kicks.