When Newt Scamander first tells Tina Goldstein he’s writing a book on magical creatures, she asks if it’s an extermination guide. No, he corrects her, he’s writing to help his fellow wizards understand magical creatures and encourage them to protect the creatures rather than killing them. It’s a theme that is present throughout both of the movie’s main storylines and is very important in the real world as well: that ignorance breeds hate and fear, which can only be combatted with understanding.
While Newt struggles to make other wizards understand that his creatures are not dangerous – at least from his perspective – the children of the New Salem Preservation Society stand in the streets handing out flyers as their leader rants against witchcraft. What do they actually know about magic? They certainly know or suspect that it exists, and they’re right that some wizards are dangerous, but their ideas are mostly based on their own fear rather than the truth they claim to know.
This ignorant fear and hatred leads Credence, the son of the New Salem leader, to suppress his magic and pretend it doesn’t exist, probably even denying it to himself. But magic can’t be suppressed easily, and the movie makes it quite clear that the only options are to learn to control it or be controlled by it. The Second Salemers’ hateful views of magic end up creating the greatest magical threat possible as one of their own becomes an obscurial, with powerful and uncontrollable magic literally exploding out of him.
The Second Salemers are aware of magic and determined that it’s evil, while Jacob Kowalski – another muggle who encounters magic – quickly learns to see witches and wizards as not so different from other people. Unlike the Second Salemers, he has actually spent time with magic-users and gotten to know them as people. Rappaport’s Law, the strict separation of the magical and “no-maj” worlds in America, actually does more harm than good in keeping wizards safe, because it means that any “no-maj” who finds out about magic will be kept ignorant.
And finally, near the end of the movie, Credence in his obscurus form is killed by MACUSA officials – although apparently there was a deleted scene that would have shown he survived? Anyway, their intent was to kill him. One gets the feeling in that scene that the other wizards don’t really see him as a person. To MACUSA he’s a dangerous threat, although as far as they know he’s a child less than 10 years old, and to Grindelwald he’s a weapon to be used and discarded. Only Newt, who has worked with and tried to help obscurials in the past, and Tina, who lost her job for trying to protect Credence from his mother, realize he’s human and try to save him. Again, ignorance makes people look at each other in fear, while understanding leads to compassion.