What is meant by this paragraph:
109 "The criminal is often enough not equal to his action: he diminishes and disparages it."?
What is the underlying belief of nietzsche here?
In the spirit of his superman, he wants great and impressive deeds, done "beyond good and evil," and so perhaps crimes -- but impressive crimes are often committed by trivial and petty people, which makes the crime look less impressive.
If someone assassinated Hitler during WWII, at the cost of his own life, it would look less impressive if you realized that he had done so because he hadn't gotten a promotion in his civil service job.
I think Nietzsche shifts the locus of moral reasoning, from approval of others, and relational to and contextual within a shared metanarrative, towards an intensely personal process, capable of being endured through 'eternal recurrences', even unable to change anything.
We don't describe the killing a cat does as evil, even when it cripples and tortures it's prey (most people don't, anyway). Perhaps more importantly, the cat doesn't care what we think, it's behaviour arises spontaneously from it's nature.
But, Nietzsche doesn't value violence or cruelty in themselves. He describes metamorphesis' from self-reliant camel, to fearless lion, to a higher attainment as child - and here my favourite Nietzsche quote is appropriate:
"Man's maturity: to have regained the seriousness that he had as a child at play"
What does a school shooting achieve? No glory, no legacy, only cruelty and destruction. I think he would have dismissed them.
However, I think Nietzsche might have had some respect for the Unabomber, who wrote a lengthy manifesto and was willing to take any measures to stop what he saw as the wrong direction for society, including death. A 'typical' criminal might have gone with the insanity plea Kaczynski's lawyers advised, 'diminishing and disparaging', rather than laying claim to the crime as arising from a full knowledge of himself responding to his understanding of the world.
But Kaczynski failed. Providing values, and I think implicitly social cohesion, was core to what Nietzsche admired, for instance about Napoleon, who got pretty much the highest degree of approval he gave anyone. An ubermensch provides culture and era-defining narratives, epics, that can take the place of a lost metanarrative.