Given the resources the FBI puts into each one of these cases, it's clear they're targeting people whose main crime is "being suggestible". There is effectivel

Given the resources the FBI puts into each one of these cases, it's clear they're targeting people whose main crime is "being suggestible". There is effectively an unbounded supply of those in a country of 400 million. They don't seem to care about finding those who would actually be handling the hypothetical recruitment or financing, because they don't really exist - that pattern of an externally-recruited terrorist cell is extremely rare. Approximately all instances of Islamic terrorism in the US have been either true self-starters, or people who were radicalized / recruited / trained overseas and sent to the US for attacks.