13 Harry Potter Plot-Holes (That Were Totally Solved)
3. How Was Draco Free After Becoming A Death Eater?
The "Plot-Hole"
Though he shows some contrition at the end of the Deathly Hallows, Draco Malfoy is a Death Eater who wears a Dark Mark and who seemingly signed up of his own accord (admittedly with the influence of his father, our of fear).
He lets the Death Eaters into Hogwarts and curses fellow students in his plot to kill Dumbledore, and while that task is designed to punish Lucius (hence Voldemort intending him to fail), you can't ignore the fact that Draco is a Death Eater who pledges to the Dark Lord.
So how come he - and the rest of his family - are allowed to go free at the end of the Deathly Hallows? Shouldn't they all be in Azkaban?
The Solution
Rowling's answer to this fits with what we know of the Malfoys and their stunning gift for self-preservation:
"...the Malfoys weaseled their way out of trouble (again) due to the fact that they colluded (albeit out of self-interest) with Harry at the end of the battle."
Apparently that simple act was enough to wipe everything else Draco (and possibly more notably his father) did during Voldemort's second rise.