There are two extremes when it comes to defending one’s ideology. There are people who would kill for their ideals, and there are people who would die for their ideals.
If you look back through history, it’s not difficult to see which is the better option. We hail as heroes those who die for their principles, while we revile as evil those who kill the opposition (on a long enough timeline, anyway).
Major Western religions have all milked this fact quite successfully. Jews have pretty legitimate concerns when it comes to being victimized, and their suffering has galvanized their religion to the point of being what is arguably the most successful faith in the world. No other religion wields so much power with so few members (except perhaps Buddhists, who share a similar situation), and their longevity is matched only by Hinduism.
Christians based their entire religion on a man who died for his beliefs. It’s tragically ironic that once Christians held any sort of power, they abandoned this in favor of violence against the opposition (both from non-Christians and defiant followers). However, despite the countless abuses over the centuries, Christians have maintained a very strong victimhood mentality.
Muslims are little different, and a casual reading of the Quran will yield hundreds of passages that follow this formula: Allah sent messengers, the prophets were ignored (sometimes killed), and the people were punished. While Allah is not presented as being non-violent, His Earthly messengers certainly are. Sure, Mohammed was a marauding warlord, but try telling that to Muslims today, who are victimized both in Muslim nations by their ridiculous laws and Imperialist occupiers, and abroad, where they are despised.
This can even be seen in modern day politics. Martin Luther King advocated non-violence, and was murdered by a racist white man. Malcolm X advocated violent opposition, and was ignored… until he started to change his stance towards peaceful methods. Then he was killed by members of the Nation of Islam, which he had previously helped pioneer.
It seems like history is full of these examples, and the ones we respect most are not the people who take up arms and fight, but are the ones who oppose violence on principle and instead advocate peaceful disobedience.
So why is violence so popular?
Some people feel that if you peacefully oppose something, you are doing nothing, or not enough. There are also people who fear the consequences of civil disobedience. But how selfish is it that you would not give up your own life for your ideas, but you would sacrifice others?
If what we believe is right, dying (or accepting lesser or greater consequences) for our belief is the most powerful statement that can be made. Dying for your beliefs would only be wrong if what you believe is frivolous and stupid. For those who kill for their beliefs, this often turns out to be the case.