In my experience, Delphites ARE talking. They just closed ranks. In the early months, just saying you were from Delphi, or live there, would net you with dozens of new friend requests, each person messaging that they wanted to talk "privately" about the case. The media came out and interviewed my cousin's teen daughter and she was suddenly flooded with new "friend" requests. People would innocently share their their thoughts, only to find that their messages were screenshot and shared in the sleuthing groups. Then there were the people driving to Delphi for crime tourism, sometimes literally walking around people's yards with their cameras, trying to make YouTube videos. My aunt about had a heart attack when she found a guy out back, trying to livestream. When my uncle (75, 300lbs & bald) ran the dude off, he hollered that he was going to call in a tip about my uncle. People are nuts. And God help you if you had a picture on your page of someone in a blue jacket...
People have ideas, they have theories, they're just not being publicly vocal. And I don't blame them.
Source: firsthand experience