You are training for strength, not "sport" when you squat. Strength then applies to "sport" as a general adaptation. So, you squat the best way to squat, so that the squat can make you a stronger "sportman".
The concept of having the feet pointing out at a 30 degree angle during the squat seems counterintuitive to the direction of travel in athletics. In SS it is mentioned that having your feet pointing too forward limits your ability to squat full depth. But if you are training for sport, would you not want to engage/orientate your muscles in the direction in which you intend to use them?
You are training for strength, not "sport" when you squat. Strength then applies to "sport" as a general adaptation. So, you squat the best way to squat, so that the squat can make you a stronger "sportman".
Undestood, but I'll provide this for thought. Duncan Keith of the Chicago Blackhawks (since 2010, two Olympic Gold medals, two Stanley Cup Championships and twice awarded best defenseman) has been instructed by his trainer to squat with his feet pointed forward. Should there be no noticeable difference in athletic performance based on foot angulation during the squat?
Even if the argument for squatting with your feet forward was correct this still wouldn't make sense for a hockey player. You skate by angling your feet out and pushing off the ice. If you tried to skate with your feet perfectly forwards you'd fall over instantly.