Do People Ever Really Commit Suicide Solely In Order To Protest?

Yes, being depressed and hopeless in life is also a factor. Perhaps the Vietnamese monk was depressed in some way, like maybe seeing how his people were treated by Dien Bien Phu. On the other hand, his spirituality may have also made him willing to go through such an ordeal. Whenever someone does something so radical to protest, perhaps whatever they're protesting has made their life bad enough that they are willing to go through it. In the case of suicide bombers, though, it has more to do with glory and being misled.