Concerning these crimes committed, I'm pretty sure most of us who don't commit them can put ourselves in their shoes. The reason we can is.. we know what happens if we do, and thus we don't commit these crimes. Otherwise everyone would be doing it.
Dunno about you, but I like to think the reason I don't go around beating old women to death is
because it is wrong, not because I may be caught, arrested, charged, prosecuted, convicted, sentenced, and punished

.
At the end of the day, who does vindictive vengeance actually benefit? The deed is already done, and making someone else suffer doesn't somehow change that. An eye for an eye for an eye for an eye... and sooner or later the whole world is blind.
All you do is increase suicides in the people who might otherwise change their ways, and give hateful people more reason to hate.
When it comes to prevention, if the moderate severity crime (assault, armed robbery?) I've committed is going to result in summary execution if I'm caught, it makes no difference if I kill anyone who puts me in danger of capture or prosecution. I'm done for either way, so I may as well do anything I can to increase my chances of getting away with it :shrug:.
http://alexmasi.photoshelter.com/gallery/Halden-Prison-Luxury-detention-in-Norway/G0000.pWT7uxO5qE/ is Norway's shiniest, newest prison. Now, if you compare crime rates in http://dev.prenhall.com/divisions/hss/worldreference/NO/crime.html and http://dev.prenhall.com/divisions/hss/worldreference/US/crime.html you may notice that Norway has around 20% more thefts per 100,000 people... and half as many murders, and half as many raqes. Additionally (not from those links), only 20% of them return to prison within two years of leaving -- compared to over 60% in three years for the USA.
Convicted criminals getting better food than law abiding folks
is a fair argument... in the opposite direction from how its being used here. You shouldn't be asking, "Why are criminals prisoners getting better food than the poor?", you should be asking, "Why are the poor eating worse than the minimum standard we set for prisoners?". The problem is not that criminals are being treated too well, it is that non criminals are being treated too poorly (excuse the incidental pun). Same goes for victims of crime; if their treatment is unsatisfactory, isn't the solution to treat them better, not to treat someone else worse?
EDIT: http://www.dailymail.co.uk/home/moslive/article-1384308/Norways-controversial-cushy-prison-experiment--catch-UK.html about one of Norway's new prisons. Despite being from the Daily Mail, its not bad (the writer mostly just describes stuff and lets other people speak for themselves).