Illegal to metal detect all National Parks?

That is MILLIONS of acres. My aunt has had a house on Fire Island (off southern coast of Long Island) in NY since before I was born (I am 44). As a child my dad would occasionally hit the beach and metal detect for a bit. I have been thinking of detecting there again, but I just researched it and found out metal detecting is strictly prohibited...everywhere....including the beach....because all of Fire Island is a part of the National Park Service. Now I can understand the dunes (you are not allowed to WALK on them anyway), but on the beach? It's sand that in being dug in all over by people and moved around by mother nature anyway. Heck they could make a lot of money issuing revokable permits for metal detecting just on the beach...where everyone is digging anyway! I hate when government just issues blanket rules just because someone has the power to do it. grrrrrrrrrrrrrrrrrrrr it's SAND lol