Can someone tell me why this place has so many vandalism? Why the state don't send a group of people to clean up the place? I go bout what i see in the photos on here.

If you are referring to the graffiti it has been a street art collection area for as far back as I can remember, if you know the right places to look you can find some really well done pieces of art hidden away. Secondly it's not a state park it's a National (federal) Park, and they do infact have people that go into the old bunkers and document with cameras, then cover over with paint a fair amount every so often but the people come back, its public land with a fair majority only accessible by foot or bicycle at most. I highly recommend you don't just limit yourself to the photos, and do infact come out to see the park for yourself. It's hard to believe you're still in NYC even when you can be staring at it on one side of you and the open ocean on the other side from the top of the one bunker. Anything other than graffiti is likely mother nature.

Because it is outta the way. Its a federal park without much going on

By "state" do you mean New York state? This is not a state park. It is a federal park. There is no money for graffiti removal, and if removed, the artist and vandals would just do it all over again.