That is your definition of a martyr. A martyr is someone who is murdered specifically for what they believe in and because they will not deny that belief.
Joseph Smith, before he left to jail, stated "I go like the lamb to the slaughter", he knew he was going to his death.
I suppose it depends on how you define martyr, eh?
All of the following are definitions of martyr:
#one who suffers for the sake of principle
# one who voluntarily suffers death as the penalty for refusing to renounce their religion
# one who willingly accepts being put to death for adhering openly to ones religious beliefs.
# someone who chooses death rather than to renounce his faith.
# member of the Christian church who suffered death for their faith; martyrs ranked before all other saints.
I'm not saying I disagree with you, but none of the definitions I found on the web mentions non-violence as an attribute of martyrdom.
Joseph Smith didn't kill anyone. He had a gun and shot back in self-defense from the prison where he was held, but he he only wounded those he shot. Oh but wait... you knew that! If you had to take a test on the real truth you'd probably score higher than most Mormons. Too bad you can't turn your energy into something more positive.
What are you smoking? Joseph Smith defended his friends as well as his brother against a mob of militia, John Taylor and Willard Richards both survived because of his heroism.