Because you don't support most of what christians post. You make common christian beliefs even debatable.
But I'm asking you how will you even know that someone gets the radio messages. You may be spinning your wheels. If someone risks their lives and puts it into the hands of someone else, then they know the job is done. There is nothing wrong with doing it both ways. If you have ever given a bible to a person who has never had the ability to own one of their own, you would cry when you see their joy and gratitude. I'm sure there are people able to memorize the bible and share it that way as well...but why limit it by saying there is only one way that is proper to do it? If written scriptures were good enough for Jesus, they are good enough for us. So is memorization. But Lord help those that can't remember it correctly. No telling what we would be saying to people.