The AMP grew out of a general attempt to break the Fraternity's political clout in the early US. When William Morgan was kidnapped and possibly killed or perhaps paid into self exile, they switched gears into making many spurious assertions about the Fraternity, mostly centering on the idea that the "penalties" listed in the obligations were supposed to be literal and that that was an excuse for physically harming people who tried to leave the Fraternity.

A few points on that: other than Morgan, there was never any evidence that that was true and it's certainly not true now. Also, the anti-Masonic party quickly imploded because they had no real consensus or mandate outside of, "we're not those guys."