@The:
This is not one of those innumerable "Evil traitorous rival death-scene instant forgiveness" moments. It's not two former enemies meeting up after a being separated for a while and burying the hatchet either.
This is subduing a madman who crashed your party, mortally wounded you and had his gang beat your family to near death - and then letting him go because he happened to be your old math teacher.
This is Dispelief Stretching of the same level as when Byakuya was instantly transformed into a blameless adoring big brother. Or when Gildartz joined. "Hey dude, it was so cool when you crucified three of our members and razed our guild! Wanna join?
The most comparable moment to this scene I can think of is when Goku let Vegeta escape from earth, which was done purely for his own selfish reasons, and called out as bullshit by Krillin.
But yeah sure, for the record: I hate any scene, regardless of manga, where a hero forgives a defeated, iredeemable villain and lets him evade punishment on purpose. Why couldn't Makarov just have forgiven Hades…and sent him to jail?
Methinks you mean Gazille.
And it was just one of those pussy faux crucifixtions, where the nails are just hammered in under their arms for support. Which I'm almost certain would not work.
Also, I think Makarov doesn't know about Mest or the government being there yet. And they kinda seemed to have already left too.