There's no policy they just don't care about a 14 year old. Repeat freshman year then they will show interest when you call them as a sophomore and or older. If your son is a high honors or honors student then admissions will negotiate because the schools want great academic athletes regardless of the sport. My oldest is top in the class and goes for almost nothing. Was thrown up on varsity all three sports. There a reliability factor they take their chances on academics unless your full pay. Only other option is cattle herding selects school and good luck beating out a Canadian for a spot on the real team!!
Despite what some people may think, there are coaches out there, including the ones at the schools you mention, who feel no need to kiss the rear end of a 14-year old kid or his delusional parents. There's no "rule" - maybe they just have some pride and perspective. Kids are going to go to play for those coaches at those schools. They'll coach whomever shows up.