There is no substantive difference between the "left" / "liberal" statists and "right" / "conservative" statists, there's just the question of degree to which individual rights (including parents' rights, the natural right to homestead and defend property, etc) are violated. By that definition, all acts of violence originate with the statists, no matter if it's just one petty shoplifter, a bunch of armed anti-abortion nuts, or an organized political elite.
The
OKC bombing (assuming it really was masterminded by McVeigh and Nichols alone) was intended as an act of self-defense, and I can agree with that logic to a degree, but not completely. Adults who choose to work for a violent institution may be fair game, but how hard would it be to check if there's a day-care center in that building! There were much better targets for them to choose from...