I'm doubtful he's scamming and I believe he owns the ~150TH, but the approach he is taking is foolish. Public threats are seldom wise, it's best to talk softly and carry a big stick.

Usually, when people broadcast threats, they are just empty hope. Maybe he just has a unique personality and he can indeed fully back what he states, but actions always speak louder than words. I applaud anyone that goes after scammers, and while my pursuit of scammers are always upon legal methods, I imagine there are many places that this approach would not work.

Putting the threats in a public forum is simply a smoking gun though, and doesn't have much of a benefit for anyone.