Because, I found this on Answer.com
California is the ONLY place in the United States where productions of this type are actually legal. The production of Adult Material is legal in California due to a precedent created by a 1988 decision of the California Supreme Court (California vs. Freeman). As a result of that decision, California became the FIRST AND ONLY state where a person can be legally hired to have sex for the purpose of making Adult Material. However, producers are still required to obtain permits before starting any such production. NO OTHER STATE HAS SUCH A PRECEDENT therefore production in any other State is, and will remain, ILLEGAL!
But, Bang Bros is in Florida and I know California cannot be the only place that porn is being made its to big. That is like saying New York is the only place Hip Hop music can be made, its to big for one state to have.