From what I can find, you should be able to fly just about anywhere on that beachline. Red circles are 1.5 miles from Pier.
The Restricted Airspace is only on the mainland and does not include the actual pier:
The greater surrounding area is not in any kind of Surface Controlled Airspace:
Okay, so by all of this it looks like you'd be good to go, HOWEVER; There are NOTAMs in effect:
0/0853 "SECURITY SPECIAL SECURITY INSTRUCTIONS FOR UNMANNED FROM FLYING WITHIN A STAND-OFF DISTANCE OF 3000FT LATERALLY AND 1000FT ABOVE ANY U.S. NAVY (USN) VESSEL OPERATING, TRANSITING, OR AT PORT WITHIN THE TERRITORIAL WATERS AND/OR NAVIGABLE WATERS OF THE USA."
9/3817 "UAS OPERATORS ARE STRONGLY ADVISED TO AVOID FLYING IN CLOSE PROXIMITY (GENERALLY, IN AIRSPACE WITHIN 3000FT LATERALLY AND 1000FT ABOVE UNLESS INDICATED BY THE FAA BY NOTAM OR OTHER MEANS) TO: DEPARTMENT OF DEFENSE (DOD) AND DEPARTMENT OF ENERGY (DOE) FACILITIES AND MOBILE ASSETS, INCLUDING VESSELS AND GROUND VEHICLE CONVOYS AND THEIR ASSOCIATED ESCORTS, SUCH AS UNITED STATES COAST GUARD (USCG) OPERATED VESSELS"
And there are more. The above is just some summary info in a MUCH longer worded NOTAM I found by simply checking for TFR's and NOTAMs in the area. There's more to being able to fly there than just checking for "Class G" airspace.
But, you did say you were 1.5 miles away, and as long as you're not within the 3000-foot lateral proximity to any vessels and facilities you should be okay. Sounds like you were a little close for their comfort. Maybe next time you should check in with them first, show them where you'll be and why you're there, and that you'll abide by the NOTAMs and Airspace Restrictions. Yes, I know you shouldn't have to do this. It sux. They don't know you and don't know if you actually know what you're doing, and will be safe and abide by restrictions...or just some Ding Dong who got a drone at Best Buy and will do something stupid. It's been my experience that in a sensitive area if you check in with the authorities first, show them that you are aware of the area and all your info, permissions, and gear is prepared and planned....they'll be much more accepting of your activity.