Should Batman kill the Joker?
The argument goes that the Joker is an unrepentant mass murderer with a lengthy documented history of violence. He laughs in Batman's face that he is only going to escape again and commit more crimes. Batman knows in all likelihood Joker will escape Arkham Aslyum again to hurt more people. The corrupt Gotham justice system has failed to deal with him. Based on the Joker's pattern of behavior, the city would be safer if he were dead. Since Batman wants to keep the citizens of Gotham safe shouldn't he either kill the Joker or at least let him die when someone else shoots him instead of saving him?
The Doctor (from Doctor Who) knows the Daleks are a race designed in both nature and nurture to have a xenophobic hatred for every other non-Dalek race and desire to destroy them. Over millions of years, they have exterminated whole galaxies. The Time Lord High Council once sent The Doctor on a mission to prevent their creation, in violation of their non-interference policy, citing the threat the Daleks pose. Yet The Doctor refused to carry out his mission and constantly looks for a "good Dalek" only to be forced to kill large groups of them time and again and witness the horrors they inflict throughout time. The only known "good Daleks" were either brain damaged or specifically created to be more free thinking and went through experiences that would be very difficult to replicate.
Wouldn't the universe be better off without the Daleks? What price is the possibility of one "good" Dalek worth in blood other races pay? The Doctor also spares reoccurring enemies like Davors and The Master only to watch them abuse his mercy by repeating they crimes. At times, he even regrets his mercy seeing the harm it does others. And ironically, for a pacifist The Doctor has rendered a number of races extinct.
Marvel's Odin- The dragon Fafnir was once king of the land of Nastrond. Odin destroyed the land and all of its inhabitants for its wickedness.
In fact, this is a kind of common trait in mythology. The gods getting tired of a land's evil and wiping it out to start over.
Future Old Thor from the Gorr time line once boasted of rendering the Frost Giants extinct though he did not disclose the circumstances.
Thor: The Dark World - Bork nearly exterminated the Dark Elves (admittedly with some help from Malekith himself) and Odin did not consider it a bad thing considering the threat the Dark Elves posed and that it brought about thousands of years of peace. Thor and friends never really comment on it and when they finish off the Dark Elves are not broken up about it.
The Dark Elves and Fire Demons have a long history of wars of aggression against the other races of the Nine Realms. The Dark Elves willingly made Malektih, a known madman their king despite being presented with a another option. Waziria chose to take his place. The Fire Demons have time and again tried to burn the other realms. The Queen of Cinders and her army are gleeful about it.
Defeating the Dark Elves and Fire demons has not brought about any lasting peace. And both come across as far more dangerous than trolls or frost giants.
War Thor had an opportunity to trike a major blow against Malekith war effort by laying waste to Muspelphim only to be stopped by Jane-Thor. Currently, their is no large resistance to the Dark Council. Asgard is neutral. Alfheim already fell and the dwarves were not far behind. Jane-Thor and Odinson have been sidetracked by their own problems. War Thor was the only one that came across as making any progress.
Given what is known, what is the solution? Should War Thor have been allowed to strike that blow against all of Muspelheim? What is the price in Light Elf, dwarf, and Aesir blood? Could a lasting peace be established if Thor summoned a flood upon upon the Dark Elves and Fire Demons? What if Malekith and the Queen of Cinders started trying to use children has civilian shields or send them out to fight like Hitler did during World War II?
Again, I am playing Devil's Advocate and looking only at extreme cases. But it appears both races are for one reason or another so hostile that they start these horrible wars for no reason other than they want to compared to Light Elvs, Dwarfs and gods that mostly get along. The intelligence of the Dark Elves and Fire Demons makes them more dangerous then giants or trolls.
Is there a limit how how much mercy and tolerance should be shown them when their species choose to engage in their behavior time and again? Is there a solution? What if they are inherently that prone to violence?
These are the questions I am trying to look at.
First, I'll answer this:
"Should Batman kill the Joker?"
The Joker isn't "potentially" evil - he has committed evil acts that warrant justice be delivered for the victims.
The Daleks have been shown to be evil, but also have the occasional one who isn't. That said, Doctor Who is a VERY different story than a superhero one. Yes, I think it's silly when he was upset at his doppleganger when he blew up the Daleks who were about to wipe out all of existence. Daleks are just another example, however, of lazy writing.
Old School mythology isn't the same as Marvel's THOR - even Odin isn't the same as Thor. Odin's a douchebag. Thor's a hero.
You're asking a crap ton of questions, and my question in return is simply - is it something you want to READ? This is a comic book. Do you want to read about those kinds of events? Do you want to see Spider-Man running around, snapping children in half while the Hulk rips the arms off the elderly? Yeah, they might be evil - but it's not a good narrative.
The point is, a good writer would write stories that would make YOU, the reader, question the idea. If you consider it a good idea to wipe out a race, then that writer is not doing a good job. A better act would be to see Thor assisting a small but dedicated rebel group bent on overthrowing the Fire Giant Queen. That's a story worth reading. Not needs some killin'.