the handful of cases where it had the intended effect were so successful that it makes sense that others would do the same hoping to get the same reaction (the Tibetan monks, the Arab Spring, etc)

There’s no way to objectively determine if self immolation is “effective”. Take Tibet, yes it’s a famous photograph, but did it free Tibet? Was the monks goal to become a famous image, or was it to end the cultural genocide?

What about the Arab spring? Was that man’s goal to kick off a movement that would eventually destabilize the entire region, leading to more autocratic governments securing power?

Is self immolation a powerful act? Yes, but power without direction is meaningless. Real change requires collective action, not independent acts of “psychological warfare”.