Draco Malfoy obviously struggled with his actions in Harry Potter, and he was much more deserving of a redemption arc instead of Snape. There is a lot of controversy among Harry Potter viewers over Snape’s redemption arc, especially due to his treatment of Hogwarts' students. A major theme of Harry Potter is good and evil, but more so that people are not solely one or the other - which gave the complexity of Snape’s actions some justification, whether he deserved it or not. The audience learned about Snape’s past throughout the Harry Potter franchise, leading to major reactions when it was revealed that he had been helping Harry throughout the story.
There is no doubt Malfoy was a bully in Harry Potter and showed this from first entering Hogwarts. Malfoy is shown to be similar to Harry - both clever and ambitious - but Malfoy obviously leans to the darker side of Wizardry. In Harry Potter and the Chamber of Secrets, it is clear the influence Malfoy’s father has on him and how this has directed his beliefs. As Malfoy gets older, particularly from Harry Potter and the Half Blood Prince, it is clear he begins to doubt his actions and who he is fighting for, shown by lowering his wand against Dumbledore and his position after the Battle of Hogwarts.
Malfoy Deserved To Be Redeemed
Malfoy’s upbringing does not justify his actions, but instead supports the notion that he deserved a redemption arc over Snape. As Malfoy matured it was clear he started to doubt his actions, and though Voldemort's Death Eaters viewed him as a coward, for audiences this was shown more as a battle of his conscience. Draco was only made a Death Eater as punishment to Lucius Malfoy, and if this had not happened, Malfoy may have had more chance to change his ways. Malfoy’s parents’ influence, mainly his love for his mother, is what keeps him on Voldemort’s side - but Draco had many opportunities for redemption that were not explored enough.
Malfoy’s battle with his own conscience in Half Blood Prince - and his hesitation to rejoin Voldemort after the Battle of Hogwarts - shows how close he was to a redemption arc. In fact, a deleted scene of Draco Malfoy from Harry Potter and the Deathly Hallows originally had him throw Harry his wand, which shows this was almost part of the movie plan. Malfoy could have been the perfect example of Sirius’ quote that no one is entirely good or bad, but it is their choices that define them. As Harry's in-school nemesis and foil, Draco deserved defined growth to represent how people can defy their upbringings and change.
Snape Didn’t Deserve A Redemption Arc
This representation of people being both good and evil was instead given to Snape, who did not deserve the redemption arc to the same degree. Where Draco Malfoy could have unlearned his childhood ways to truly change and do good, Snape was only good when it benefited him or satisfied Snape's love for Lily Potter. Even if Snape was acting as a double agent, his merciless bullying of students, especially Neville Longbottom, had no justification and showed he still ultimately appeared to consider some others as lesser.
Also, it is questionable whether Snape would have renounced Voldemort if Neville had been The Boy Who Lived, as the prophecy could be interpreted that way. Snape only told Dumbledore about Voldemort’s plans to kill Harry because Harry was Lily’s son and Snape did not want Lily to get hurt. Dumbledore used this to keep Snape on his side and, as his Patronus shows, Snape never stopped loving or wanting to help Lily. Snape may not have been the villain, but his actions came from a selfish place, whereas Draco Malfoy's potential Harry Potter redemption arc could have showcased a less self-focused example of character growth.