Maybe he wouldn't get grief from you no but he'd hear it from the GK coach after the game.He'd have got no grief from me. Dunk / Webster should have been capable of cleaning up that long ball without Sanchez getting involved, or at least holding things up. There was no need for Sanchez to come charging off his line, he just confused things and made matters worse.
I'm not saying Haaland wouldn't have scored had he stayed on his line, but he would at least have had someone else to beat. It was a big misjudgement on his part that led to a simple finish.
You teach keepers very early today that they need to leave their goal line to intercept balls and to cut off angles for the opponent.
Sanchez saw the long ball from their goalie, he saw the sprint duel between Dunk and Haaland and thought "ok so ye either I go out here and try to get to the ball before Haaland, or Haaland will have a one on one with me glued to the line and he'll score a 100% of his chances in that position". He decided - like any profssional keeper would IMO - to leave his line and try to deal with it, but misjudged it.