Ya just shot yourself in the dick by the way " only a concerned citizen" doesn't have the legal or societal right to go chasing after and confronting folks. You REALLY blew your arguement up with that.
Actually, I do have the legal right to speak to ANYONE, for any reason. They have the right to tell me to fuck off when I do speak to them. You surrender ZERO rights to self defense for initiating conversation. Now if you go touching someone, threatening them or assaulting them, that's a different story.
I have been in the situation in my own neighborhood, with a local sex offender that started cruising our area, sitting in his car watching the kids play right in front of our homes. All the neighbors were buzzing and texting and whispering. Cops were called out several times, but never showed up in time to harrass him. The last time we ever saw him was when I went out with my next door neighbor, who happens to be a captain in the Special Forces Regiment stationed here at Bragg, to have a civil chat with him. I have a concealed carry license for NC and you can be sure I was carrying. The police are a reactionary force, they are not here for your protection, they are here to make arrests after the fact. As a sentient lifeform, you are charged with your own protection. EVERYONE has that right, whether the current government recognizes it or not. I'm taking care of my business no matter what, if I gotta go to jail to protect my family, so be it.