The FBI says there was.

The SPLC is not a source. You should also notice the language in the article. "Cache of radioactive and other dangerous materials suitable for building a "dirty bomb,"" can mean literally anything. They even use "dirty bomb" in quotes. You should also understand that the FBI will infiltrate and supply materials in order to make an excuse of arresting them, thus creating criminal activity where there otherwise wouldn't be.

Bullshit. All you could think of as an example were a group of clowns from half a century ago who let off a couple of pipe bombs.

You're pretty ignorant if you think that's the only example. I provided a book filled with examples. Leftists have also bombed senators homes, have attempted assassinations of presidents and senators, have burned downed buildings, helped place soviet spies in the government, started riots, and so on.

Off the top of my head, I can mention assassins of civil rights leaders, Klansmen who blew up a church with little girls in it, murdered three college students trying to register black people to vote, right-wing nuts who blew up a fucking federal building with hundreds of people in it, shot up a Jewish daycare center, murdered a Jewish radio host for criticizing white supremacists, massacred a church full of black people in Charleston, blow up abortion clinics and shoot doctors...murder is endemic to the right-wing.

You're lumping in a lot of one-off nobodies as 'neo-nazis.' I'm talking about organized terrorist activities. The kind that led to mass arrests and even deportations.