You need a fishing license because the guys in green/blue with the fancy stainless steel braclets and guns SAY you need a fishing license. They say you need the license because some person (usually elected) said "You need a license to fish". Sometimes this is about wildlife preservation, sometimes its about 'revenue streams' and believe it or not, sometimes it's about politics

Don't ask about hunting license politics. I know one of the game officers who is involved in figuring out what the hunting license laws should be in NY State from the pure wildlife conservation point of view. Then they have to temper that with politics and "tradition" - it turns out at least in NY, revenue is a distant 4th, with what is best for the wildlife 3rd, and politics and tradition as 1st and second