Self-sacrifice, yes - sacrificing yourself when it is necessary to do so. "I'll hold off the zombies, you make for the zeppelin without me." Or taking a bullet for somebody else, etc.
But self-immolation is like suicide by hunger strike. Unnecessary (it's not "you set yourself on fire or we kill everybody in town") and doesn't directly damage the people you're fighting against. If a cause is worth dying over, isn't it worth killing over, too? You douse the other guy with gasoline, and set him on fire.
S-I just doesn't make sense to me.
if you believed that you could foment needed change by
a) going to war killing many of your enemies as well as having many of your likeminded friends die
or
b) lighting yourself on fire to draw the attention of the world to the wrongs being done which is the better course?
add in being a Buddhist
your comment about it not making sense to you is symptomatic of the american failing in the east. we go at it expecting things there to make sense in a western context, and we plan/act accordingly. results in us getting our butt handed to us
find the film of the monks imolating themselves they don't move, they sit still as they cook. its spooky