Why is the zimmerman case being broadcast live?

because they don't allow cameras in the courts where you live and it is interesting/comical that a man can be charged with 2nd degree murder based upon no evidence.

That's my excuse... you can borrow it if you wish

For one reason only - there is a huge audience of people who wish
to see and hear it.

TV networks do not devote time to anything that viewers don't care about.

Their advertisers pay them according to the number of pairs of eyes that
the ratings companies count watching their programing.

people want to watch it, based on how many commercials they are showing, it must be getting high ratings. I don't know why you are watching it.

maybe after years of watching fake trials on TV you find it interesting to see how a real murder trial occurs, that's why i'm watching it.

when you really look at it, its like a sporting event, two opposing sides, commentators second guessing the "coaches" (lawyers) actions, only the results here actually matter.