hmmm.... i disagree that they need to pay for their sexual
offences with their lives, though.
tougher punishments like humiliation, more caning and long
years of hard labour (well, they can't just live off taxpayers'
money in jail) should be good enough....
but repeat sex offenders or serial rapists ought to be
castrated/de-sexed, so they can only screw themselves, and not
others.
I don't agree with you too.....
So when the rapist have served his sentence in prison, got
desexed like an animal, got punished/humiliation, you expect the
rapist to repent or could you imagine the rapist to become a more
twisted criminal upon release from prison?
Do think about the victims who will have to live out the rest of
her lives with this emotional scar and mental trauma that she have
been raped by this disgusting guy who can still haunted her or may
even have a normal family to raise his own kids(if no
desex) to be future and smarter rapist like himself?
The world is willing to give criminals like a rapist to have a
second chance in their lives, BUT can the world HEAL or make the
victims FORGET that they have been raped???
Rapist MUST DIE!!! 
Rape is a more inhumane crime than you imagined, even more
terrible and disgusting than murder if you can understand the crime
itself.