Although there is no real explanation of 'crazy', the likely 'trigger' for Roof's actions were the Media and Government - who close their eyes to black on white crime (e.g., 'knockout games'; 'polar bear hunting'; etc) - but magnify issues when a white, or white Hispanic, kills a black youth (Zimmerman, and the Ferguson policeman). This set off an easily unhinged Roof who ended up murdering black skinned Christians who would have been his friends in need.
If Haley wants to blame someone besides Roof - blame her ilk in the Government, and the Media.