Not exactly big names though. Hyperclan only appeared in four issues of JLA and The Authority are Wildstorm, which always had a lightly different set of rules from mainstream DC and Marvel books.
I'm thinking closer to Civil War or JSA split type division on this issue.
It would be interesting to see a 'hero' creating a genocide of villains where it was question if they had become worse than what they were fighting against.
I am Queeg...
Two-Time Benbo Award Winning, Dick clowns!
Back Of The Room podcast - What comedians talk about
Carotid Artery - Daniel Bryan likes it. Right, Daniel?
It was more about the fact that the Joker wasn't guilty of that particular crime and as a result Batman didn't want the real culprit to get away with it.
As for heroes' feelings on the death penalty, I do recall one Cassandra Cain Batgirl story where she declared "no one dies tonight" and actually went the extra mile of preventing a criminal from being executed, though the man still was eventually executed, IIRC.
I did not know about that plot by Priest. Sounds interesting.