"so the government should not be in the business of killing people."
But as a species, we're a long way from selecting government officials who don't want to kill. These freaks crave power.
And Glossip had the chance to take life if he confessed. He chose death. Just goes to show that cruelty is subjective.
The logical next step is, "so the government should not be in the business of killing people."
Life in prison? Sure, though I'm personally not sure depriving someone of their freedom for the rest of their natural life isn't also unacceptably cruel.