It has everything to do with it. Some see killing a molester for the crimes that he or she did is justice. It's not only logical to execute someone for their serious crimes but also morally justified. 

Option 1. Society pays for the room and board of killers, raptists and molesters for life. Sometimes we release them and they do it again.

Option 2. We execute them and bury them in unmarked mass graves then plant a rose garden on them. They stop being a burden to society.

so even death wasn't enough of a punishment, they also need to be denied a decent grave

Does it sound sadistic to think that those who are worthy of the death penalty shouldn't get it and should suffer in life instead?

i'm clearly against a death sentence, actually against the american system of hard punishment as a whole.

main reason, i absolutely don't see this system work. it might feel right in an eye for an eye way. but it does not work. it does not believe in any criminal actually change. and so on.

i do see the need for a real live long imprisonment for very few cases. like german sicherheitsverwahrung. you could roughly translate that as safe custody. that would be something for a serial killer or serial rapist.

Yep. If you have to put someone to death because they refused to live as a civilized person and treat others with decency/respect then why not. 

well if justice system is not meant to be for revenge then i am FOR.

with life sentence you could torture them for years.

Only in very extreme cases and obviously when it's 200% clear. The Boston guy being one of them.

In our case, the government is the criminal syndicate. lol!

It's pretty much abolished throughout all first world countries, and even most third world countries who still have it haven't used it in over a decade. Why is it still a thing in the US? Why don't you modernize? What is wrong?

Depend.
But in some case, yes, approve.