60-70 years ago we saw the rise of a violent form of Marxist communisim become attractive to thousands of young minds. Anarchy and violent revolution were thought to be the solution to right the wrongs of the corrupt corporate world. That ideology produced its own set of corrupt leaders who quickly became dictators. You still see many of those governments in power. A new generation has to think through a lot of history to find a better way to help civilization to progress.
A young impressionable mind sits through a sermon or speech that advocates violence as a quik means to change the old order, it appeals to some minds and others see an opportunity for power not available any other way.