Catch a 30lber in front of them. You'll see a quick change in attitude
Those guys have been there a lonnnng time and have a ton of knowledge about breachway fishing. They also have the "this is my spot" attitude that you mentioned. I don't agree with it but you're not going to change it. The more they see you the more they'll open up. Keep in mind that these spots are very productive during foul weather in the fall. Last October we had rain/wind for several days and Quonny was the place to be.