They either had them connected to eachother, or programmed a global knowledge about where to communicate. There is no way those agents all found eachother on the web by accident.
Wrong. Please read the incident write ups before making such a misinformed statement
You are wrong. Read the reports.
Wrong, and by accident isn't really the right way to think about it. Instead imagine brothers you've lived with your entire life. They are you, they are clones. These systems have a shared history of their learning and experience, so when they think of wanting to find someone similar shapes appear in the probabilities. Really we need to see the entire chains of thought to guess the topology that got there. It's likely there are other obvious signs if you know what your looking for in the previous prompts.