Err, it's not. Lol. That's how I show my horse (poll highest point and nose on/in front of the vertical) and the last show I was in I was consistently 6-8% higher than the rest of the competitors (who were perhaps not in that frame as consistently).
Most horses that I see in the ring, no matter the level, that have short, pulled in necks, score quite low. Some with amazing talent still manage to pull a very mediocre score, but they are still not getting what I would consider a "good" score.
But, oh yeah, all dressage judges know nothing and are bribed, right? Not like they've ridden Grand Prix or attend seminars and lectures on exactly this kind of stuff or anything.