Why can ender have friends but not parents

Ender was basically being manipulated at the academy, not brought up. Any emotional or coming of age issues he faced were closely watched and manipulated to achieve a desired response, a response solely for military application against the Buggers. As you can guess, this would not be good for Ender's maturation into a young man who enters civilian society. Ender was meant to be a leader rather than learn from adult parental figures.