The following article is another example and great explanation of why you don’t need to specialize before HS.
Experience and Wisdom from a Basketball Parent was written by Athletic Development coach Tracy Fober who has a lot of experience enhancing the athleticism of basketball players. The article also has great advice from a parent when it comes to developing your child in a healthy manner and what to look for when searching for club teams.
http://www.ironmaven.net/2013/03/experience-and-wisdom-from-a-basketball-parent/