That was not the issue I would have guessed to be your turning point. Personally, I'm more offended by torture. I doubt you are going to be writing a brief on that any time soon, but just saying.
I don't see the death penalty as about authoritarianism. I'm not sure the Soviet Union had a death penalty outside the military context. They didn't need one -- they just sent everyone to the gulag. I see authoritarianism as about due process.
I also don't see the death penalty as an important issue for me. In many ways, it feels like a trap. It's one of those issues where liberals are out of step with the population. We are going to do some things that don't have majority support; is this how we want to spend our political capital? What Zeldin just did at EPA will kill way more Americans than the death penalty ever could. Global warming will be the biggest killer in the history of the species.
I would easily trade a world without death penalty and a 2 degree rise in temps for one with death penalty and a 0.5 degree rise in temps.