Well, firstly it should be known what John Brown was and what he did. John Brown was an radical American abolitionist back in the 1800's when slavery was still legal. He believed that only through violence and force could slavery be ended. He was known for going to house to house looking for those to claimed to support slavery, dragging them to the streets, and brutally beating or murdering them. Now, when one uses the word "justified", it should be expressed in what context we're speaking in.
Morally: Was what he did morally justified? Well, no. Killing people is never morally acceptable unless in severe instances of life and death. And while yes, slavery is a terrible and cruel way to to treat any human being, there are more effective ways of making something such as slavery illegal. That is why we have a government, to tackle situations in a civil manner.
Efficiently: Was what he did efficient towards the effort therefore making it justifiable? No, it only made people scared of him! Whenever a slave started a small revolution, all it did was make the slave owners treat the slaves harsher to make sure no rebellion came again. John Brown gathered a group of abolitionists and raided an arsenal to take a pro-slave town hostage, only to be met with a Confederate army. His actions only made those like him more of a target than before by the South.
Historically: Does history show this man as someone who did terrible things for the greater good? Well, in a way. We see him as someone who knew what the right thing was, and his actions would be a small gear in what would become a giant machine of fear and distrust that would start the Civil War. But the same goes for Harriet Beecher Stowe who wrote "Uncle Tom's Cabin", and by writing this simple book that exposed to the North the horrible conditions of the slaves in the South, she got more recognition and according to legend, Abraham Lincoln supposedly said, "So you're the little woman who wrote the book that started this great war." This underscores the public connection she made with both sides, and John Brown on the other hand doesn't have as much connection with people except fear that he creates.
In short, morally he was incorrect, was inefficient with his tactic, and historically is undermined by one who chose the pen instead of the sword. No, his actions are not justified, and could have been done in a more efficient way.
Rule #37 of History:
People show us what they did, so we know how to be even better.
