The only rub against execution to me is the risk of executing the innocent.
Right, so why is that not a total disqualifier then? Even if the risk is fleeting small, there is no taking it back. If it came out later on, dead is dead. Combining that with the fact that executions are obv a psychological cluster fuck for everyone who deals with it, especially the one executed, and the fact that it takes a lot of resources every trial because it's such an unusually cruel punishment, the arguments for it are dwindling.
Also
You know what else is cruel? People killing other people.
Right but we're not voting someone in office who can eliminate all homicides in the United States. Things are different for execution.
We could also talk about how this "well tough shit" opinion always fucks over positive and healthy change, but that's probably the least impactful argument for the folks who still bank on executions as some sort of greater good.