I'm not a fan of barbarism or prison in general, but actually I think that using your position at the apex of one of the world's leading banks to squeeze money out of people at the bottom of the pyramid* qualifies as criminality.
* Whether you consider the consumers or the low-level tellers who set up millions of shadow accounts to meet otherwise impossible performance goals to be the bottom layer, I think the point stands either way.
I'm perplexed by your use of the word 'hardened.' Perhaps you meant 'violent' but there are plenty of people in prison who had a clean record until they committed a violent crime of passion or suchlike, and likewise there are plenty of criminals whose criminality is unquestioned but who never engaged in any violent activity. Again you probably didn't intend this, but I can't help feeling that you're unconsciously making a class distinction between stereotypical blue collar heavies who help themselves or carry out break-ins, vs the sort of nice socially acceptable behavior of sitting at a desk signing corporate documents which will affect thousands or millions of people that the executive has never met and knows nothing about.
Look, I'm sure you just had some generic 'tough guy' in mind, but it's not like I'm demanding the guy get thrown into some hellhole and raped int he shower every day. I'd like if we could have humane prisons like some countries, far fewer people in them, and that they should form a representative cross-section of society.
Really, if you don't have some sort of institutional accountability then it just increases the incentives to do this sort of thing precisely because the upside benefits are so much larger than the downside risks. OK, Stumpf's professional reputation is in tatters and it's probably had a negative impact on his social life...but he can basically afford to spend the rest of his life on a yacht. People suffer worse consequences from divorce.