As H/S-ing gained more and more "street cred" as a result of the high(er) scores on standardized test accomplished by H/S kids .... several state legislatures began to feel the pressure to "allow" home schooled kids to participate in extra-curricular activities --- clubs, athletics, etc .... thus the after-school sports programs @ the public schools. My son went to the same High School that I did as a result of a move from the South .... where the public school systems were ... shall we say .... "challenged" in many respects.
See ... home school-ing parents still pay taxes for the public school programs. Simple, yes???