Snape is the Hero We Needed but Not the Hero That Deserves Veneration

    Snape played a vital role in winning the war against Voldemort and he does posses some redeeming qualities as well as a pitiful backstory. However, his backstory is not so pitiful, nor his decent qualities so grand as to erase the many, many wrongs he commits and his serious character flaws.
      His backstory of his sad life with his bleak parents is sad. But it far from makes up for his actions as an adult. He retained his ability to rise above his pitiful home life and failed to do so. Even if you (mistakenly) believe that a poor home life (which his was sad but not overly horrible) earn the individual a free ticket to behave poorly the rest of their lives murdering and aligning yourself with the perpetrator of genocide is unforgivably past what can be in good conscience excused.

     The one redeeming quality everyone references was his "love" for Lilly Potter. This is an unhealthy obsession, not love. He maintained a fantasy of a young girl he knew and convinced himself it was love, much the same way tween girls convince themselves they are in love with a celebrity of a boy in their class they've barely talked to in their life. This is an unhealthy example of obsession not love. This misdirected affection does commit him to Dumbledore and keeping Harry alive but he does so in a remarkably hateful way.
     All of his misdeeds do not remain in the past, as they should if he were to truly be redeemed in my eyes. He did become incorruptibly loyal to Dumbledore but that it. He is such a abhorrent teacher he is literally one of his pupil's worst fear. This cannot be emphasized enough.  He is so inexcusably horrible to both Neville and Harry that he will never truly be a hero. He greatly abuses his power over them, starting at age eleven. Eleven! Throughout these already difficult and vulnerable years he tortures both Harry and Neville as much as he possibly can (which is a ridiculous amount). Even he other students that he has no reason to signal out with vehement hatred he mistreats. This alone discredits him from the admiration as the hero of the Harry Potter Series. He plays a necessary role, and deserves some  credit for that and  some compassion for being such a sad individual at most.