That's what they tried to sell the public. They tried to use NFA charges to coerce Weaver into being an informant. He refused and went home and stayed there. The Feds went pooping and snooping on the hill, shot the dog, the kid returned fire, and they killed Weaver's 14 y.o. son. In the end, the Feds had killed Weaver's son, Lon Horiouchi (FBI "HRT" sniper) shot and killed Weaver's wife (while holding the baby), and the family friend had been wounded also. One US Marshal (Deegan, iirc) had been killed in the initial exchange.
Bo Gritz was the one who helped end the standoff. Gerry Spence took Weaver's case pro bono.
Entrapment, coercion, and murder by the Feds.
Weaver's beliefs may not have been mainstream, but he didn't go looking for trouble, they brought it to him.