I Care About Homeless People

Why do I have to get a permit to feed homeless people? I just found out that if I don't have a permit, I could be fined or arrested. I'm just wondering because I bought a homeless man some food and water yesterday and decided to research what types of food are best to give to homeless people, and then I found out that giving them food without a permit is illegal in my state and other parts of the U.S. I don't want to be fined or arrested just for feeding a hungry person so I guess I'd better get a permit before I do that again.