Castle doctrine laws are not what most people think. There are actually only a few circumstances in which deadly force is justified.
It is exactly what people think it is.
The Joe Horn shooting controversy occurred on November 14, 2007, in Pasadena, Texas, United States, when local resident Joe Horn shot and killed two burglars outside his neighbor's home. Recordings of Horn's exchange with emergency dispatch indicated that he was asked repeatedly not to interfere with the burglary, because police would soon be on scene. The shootings resulted in debates regarding self-defense, Castle Doctrine laws, and Texas laws relating to use of deadly force to prevent or stop property crimes. The illegal alien status of both burglars was highlighted because of the U.S. border controversy.[2] On June 30, 2008, Joe Horn was cleared by a grand jury in the Pasadena shootings.
tl;dr if you're an illegal, and you steal a TV, you can be shot and killed.