When people over a certain age hear "Castro" we think of Fidel. Fidel Castro was the leader of a revolution in Cuba in another century. He created a communist utopia which has been very successful for the leaders and a disaster for everyone else -- just like all other communist utopias before and since.
For the low information voter, Fidel was Che Guevara's Cuban boss.
But now, "Castro" is Joaquin Castro, the U.S. Representative from San Antonio, who arrived on the national scene at the 2012 Democrat convention. And with the wind of the main stream media at his back, he'll be a presidential candidate some day if racial identity politics mean anything.