A person can be killed instantly through many different means.
As we know it, to be killed painlessly, is to be killed instantly.
If you instantly destroy a person's entire brain then they died without pain.
Yet the most effective ways of instantly destroying someone's entire brain are considered inhumane.
If instantly killing someone by smashing their head with a massive rock, or shooting them in the brain stem is inhumane, then there is no humane way to kill someone at all.
Most people are subject to the death penalty. The world population is approaching 8.1 billion souls. The ten most populous nations are India, China, the US, Indonesia, Pakistan, Nigeria, Brazil, Bangladesh, Russia, and Mexico, adding up to 4.6 billion – over half the planet.
Of those, only Mexico has abolished the death penalty (though Brazil is listed as “extreme only” and Russia is listed as “suspended”, having not officially executed anyone in the past decade*). Putting these together, at least 4.1 billion people out of the “first 4.6” that I looked at live under the specter of the death penalty.
I don’t think you can no-true-scotsman your way out of the simple fact that it’s still “normal” for humans to kill other humans. I also don’t think that acknowledging that fact requires that you endorse the practice.
*whoa, is this a case where RUSSIA is more sane than the USA?! Strange times.
I looked up the population info on https://www.worldometers.info/world-population/population-by-country/ and cross-referenced with the site you posted.
To understand why it’s legal in the USA you have to first understand how the US’s government is structured. The Federal Government actually doesn’t hold that much power, the most power is held by the States which decide on issues like this for themselves.
https://www.pewresearch.org/short-reads/2021/07/19/10-facts-about-the-death-penalty-in-the-u-s/
Oh, I understand quite well why it’s legal in the US. It’s been a topic of some debate my entire life here.