By skyforbes 
Black Ops 2 is one of the few CoD games focused on player decisions and altering the story based on what happens. While sparing Menendez can get you the better endings if Karma is still alive, if she died, you get one of the worst where he escapes, kills Woods and then himself. It's a lot more interesting of a take than killing someone beyond saving or that it's always the correct decision to spare someone.
[Bad Example] Joker – Batman Ninja
Joker himself could probably fit here but it's generally more of a coin toss depending on the writer and how bad Joker's crimes are. In Batman Ninja, Red Hood corners Joker with the intent to kill him, but he seems to have lost his memories. After a lot of begging, Red Hood eventually lets him go… only for him to instantly regain his Joker memories and become the BBEG of the movie, which sort of reinforces the idea Jason should have just killed him. Since it's a Batman movie, however, he's spared in the end anyways and this moral decision mostly just serves as a way to reintroduce Joker to the story than have any kind of point.
[Funny Example] Malgosha – A Minecraft Movie
One of the few unironically funny jokes from the movie comes from the villain playing into the 'villain begging for mercy only to betray the heroes' cliche, which is probably one of the most common tropes when writers want to make the protagonist seem virtuous while still wanting to kill off the villain.