More than that. Depending on exactly how you want to classify Shea and the groups that have similar goals and political leanings, you can lump him in with all kinds of anti-government "patriots" from sovereign citizens to Mormon fundamentalists, to organized militias. Even narrowing things down to include other Christian separatists in the PNW, there's an increasing number thanks to the decades-old
Northwest Imperative movement that specifically encourages people with Shea's political leanings to settle in the PNW with the eventual goal of creating a new state; AFAIK, no one has exact numbers, but from following this stuff for a few years, it's way more than hundred. If you're interested, the podcast Bundyville does a pretty good job of summing up the impact and reach of people like Shea, especially in its second season. It's not comprehensive, but it's a good introduction.
It's easy to dismiss people like Shea as powerless whackos, but that's short-sighted and ignores how widespread his beliefs actually are. I'm increasingly convinced that if any domestic threat to the US manages to be successful, it's going to come from the "Patriot movement." It's already widespread, and has been increasingly getting legitimacy through people like Shea (and even to some extend Trump, with his rhetoric and certain actions like pardoning the Hammonds), and incidents like the Bundy standoffs, and Oregon state senators partnering with the Oath Keepers. These groups cast a wide net, relish violence, and are increasingly being emboldened by mainstream figures. As far as the boy scouts handling the situation goes, Shea has been a scout master in the past, so...