You saw this particularly during the 90s, when people were radicalized to attack and kill abortion doctors. It was rarely called terrorism, but the tactics were the same.

The folks who sent hoax anthrax packages to Planned Parenthood offices where mostly lone actors, picking up on their group's radicalizing messages.

One could also say Eric Rudolph and Timothy McVeigh were "lone wolves" in that they believed the radicalizing talk, but acted essentially alone.