As explained there in an excellent way, performing deadlifts with a too upright trunk (or, equivalently, with hips too low) is not optimal as it puts the shoulders behind the bar, instead of above the bar. That's not optimal as the delts aren't able to hold the barbell in a partial front raise position with the load a person is supposed to use with deadlift.
However, I've seen plenty of Olympic Weightlifters assuming a very upright torso with shoulders even behind the bar during snatches. That's a tipical picture (shoulders slightly behind the bar, or anyway at a limit position I've never seen in deadlift):
I'm curious to know:
Which advantages this position offers for them in Snatch
Why loading the front delts in this way is not a concern