Billing information

Why do you need to re-enter all your billing information if your trying to update FREE APPS? Sometimes I don't always have money in my account so it won't let me update any of my apps until I have money in my account. This seems ridiculous! Why do I need to re enter all of my billing information to update FREE apps? It really bothers me that apple won't let me even update apps that I got for free anyways. They are free apps! Why does Apple try to make me re enter all of my credit card information just to update it!? This is stupid! I'm not making a perchase! Just trying to update!