The problem with the Death Penalty is that we would asking ordinary people to be complicit in the murder of another.
Ethically speaking, that's fucked up.
I mean, if you got the chance to put a knife in the person who was responsible for taking your child's life, great. There's a sort of "natural" justice in that. But paying someone just over minimum wage to forcibly strap a prisoner to a bed before execution is a whole lot different.
Imagine the conversation when they got home.
"Hi honey, dinners almost ready, how was work?"
" Oh it was an absolute nightmare today, we had another execution, another Get Tough on Crime things, anyway the guy just wouldn't die, we had to use three injections and a strap broke half way through"
"Oh wow, sounds rough, do you want gravy? Think we're almost out, but check the old Bisto tin behind the bread bin"
*"No, that's OK, just have some brown sauce, oh yeah, it was so funny, the guy on the table was trying to fight me as I tightened the straps again. You should have seen the look on his face, priceless, and the smell when he shit himself once we'd finally killed him!"
Anyway, enough about my day . ."*
It would just get very awkward and messy.