Alvin M. Keeling 
by Kat Nicholls
Here is a question for you. Why do you think Severus Snape didn’t reveal that Lupine was a werewolf when they were students together at Hogwarts?
I think it’s safe to say it wasn’t out of the goodness of his heart.
We know from JK Rowling’s writings on WizardingWorld Digital that werewolves were looked down upon and feared, viewed by many in the wizarding world as dark creatures that should be locked away at best, killed at worst. We also know that wizarding governments, both the Ministry of Magic and MACUSA, have a history of convicting people without trial (Newt Scamander and Sirius Black, to name a few). Put those facts together, and I think if the Ministry had found out that Dumbledore had let a werewolf into Hogwarts and attacked another student, then there’s a very good chance the Ministry would have thrown Lupine straight at Azkaban without a trial and there would be nothing Dumbledore could have done to stop it.
So why did Snape remain silent?
Here is my personal headcanon. Dumbledore threatened him, probably with expulsion and snapping his wand on the grounds that he was out of bounds at the time of the attack if he revealed that Lupine was a werewolf.
Dumbledore is capable of doing something like this. It’s not just grandfather’s kindness and good paternalism. In fact, he can be one of the most ruthless people around. He is the man who not only sets out to take an eleven-year-old boy and groom him to become a sacrifice, but also knowingly condemns him to years of harshness and abuse at the Dursleys. He’s the man who backed down and let Sirius be sent to Azkaban without trial. This is the man who, when Snape came to him as an adult and told him that Lily Potter was in danger, agreed to protect her but then demanded, “What do I get?” I think a man like that would be perfectly capable of threatening a traumatized child if he thought it was for the greater good.
Oh, I’m sure he would have been nice and polite about it. But the threat would still have been there. Expose Lupine as a werewolf, and I will ensure that you are expelled from Hogwarts and legally, if not physically, turned into a Squib. So if my headcanon is correct, then, first of all, it’s blackmail. Second, it’s exactly the same thing that Headmaster Dippet did to Hagrid and for a much more important reason (even though Hagrid was innocent of opening the Chamber of Secrets, he still passed a creature rated XXXXX to Hogwarts), and thirdly, I think it’s safe to say that Dumbledore bears some responsibility for the man Snape has become. Oh, not completely, of course. We are all responsible for the choices we make. But there is also a lot of truth in the saying that “Children learn right and wrong from the adults around them, and they learn by example.”
Snape, as we’ve seen, didn’t really have good parenting role models before Hogwarts. When he and his best friend finally arrive at Hogwarts, a place he has been taught will be so wonderful; he finds out that the teaching staff let a bunch of bullies torment and humiliate him over and over again (think Death Eaters at the Quidditch World Cup versus what James did to Snape in their fifth year) and they are allowed to get away with nothing more than a slap on the wrist.
When he finally has a chance to get revenge for all the pain and humiliation they’ve inflicted on him, the school’s kind principal threatens him with the destruction of his world and the loss of everything he likes it if he reveals that a comrade is a black creature and had attacked him. This is the same principal who did nothing to stop those same bullies from hurting him, and anyone they thought was weak.
What do you think that would have taught him? Hmm? When could they do this to him and the others and get nothing more than a smack on the hand from the adults around them? When the Marauders got caught out of bounds so many times and only got one detention? What do you think taught him about power, accepting responsibility for his actions, honor and integrity?
These are questions worth asking.
