Doesn’t high cost just mean there’s an extensive process in place to try to prevent killing innocent people (and yet it still happens). Not sure why that qualifies as “dirty” — wouldn’t killing without the process to save money be dirtier?

I think the parent was implying most of the extensive process is there in the first place because of the same opponents insisting on them.

Activists against the death penalty raise costs by frivolous litigation and then claim that the death penalty is too expensive. The same thing they've done with other things they don't like, e.g. nuclear power. It's circular logic.

No, proponents of the capital punishment attempt to create process that attempts to mitigate complaints made by abolishionists.

Nice attempt at shifting the goalposts and shifting blame. And making a false equivalence with nuclear power.

Abolishionists want capital punishment abolished because capital punishment is inhumane, cruel, and morally objectionable.