There have been a lot of theories floated in the mainstream media as to the root cause of the Baltimore riots.
One is the desperate poverty of many of the residents there. Another is the hopelessness of life in the inner city. Some say the educational system is lacking. Some blame the lack of employment opportunities for minority youth. And others say that such a conflagration was inevitable given the hostile, disrespectful attitude many police officers display towards young black men.
Here's a simpler explanation for the recent chaos:
Fish swim, birds fly.