Team GPA is not really a good benchmark of academic achievement, but that is a good start. Not citing Massillon specifically, but I would be more concerned with the percentage of remediation-free ACT scores entering college.
But to answer your question why I wouldn't send my son to Massillon, I believe that there is far more to high school than football and that should not be the defining portrait of a person who is becoming a functioning member of our society. Furthermore, the environment which I would want for my son does not include a culture in which a sport is put above the academic preparation and development of a person, in the way that Massillon does their football team. Before you call me a hater or something else, I actually think Nate Moore has brought more respect to this team than previous coaches, and really don't have anything against the football program. My issue is the culture that exists around the football team which belittles the emphasis of academic and personal development, and develops unreal expectations for young men. I am not trying to start a pissing match here, but you asked why someone would not send their child to Massillon if they played football, and I think it is a fair to say that life after football exists much sooner than many want to believe and there are far better institutions around Stark County that would prepare my son for this life.