I agree with what you're saying, John. I'd even expect these NRM people to concede something along those lines which only makes me wonder why they can't say as much to begin with. Sure the cult's responsible for engendering this kind of paranoid,anti-social thinking in the first place.
This is the part that really gets me about that though:
What can be observed in most of these tragedies is a process which sociologists sometimes call "deviance amplification" building up. The antagonists on each side behave rather badly, and that gives permission for the other side to behave more badly, so you get this spiral and increasing polarisation with each side saying: "Look what they did."
What in the world did the "other side" in Jonestown, Heaven's Gate or the Solar temple ever do to warrant any criticism, let alone an actual comparison with the sins of the cult itself?
Stupid!