Fandom can be a wonderful thing. The ability to find people who love the things you love and express that passion in creative ways is heartwarming. It's great watching people come together and discuss what they love, dress up as certain characters, and introduce new fans to their group. However fandom, like many things, can have a dark side.
Over the last few years we've been seeing fandom at its worst. We've see "fans" verbally attack and stalk actors from films (such as "Star Wars: The Last Jedi") to the point where they quit social media. Characters can be so hated, such as Jar-Jar Binks, that their actors are almost driven to the point of suicide. When casting is announced for certain characters, such as Captain America or Batman, people get furious and start talking about boycotting a film.
What causes such ugliness in fandom? Like most people who have a great passion for things, such as religion and/or country, they can take their love of something too far, to the point where it seems excusable to hurt others as long as what you're passionate about is preserved. We see various religions fight holy wars against each other and we see countries tear each other apart over differing ideologies. Sometimes passion can become to strong and can tip over into fanaticism.
When it comes to things like this I understand where some of it comes from. You love a piece of art since childhood and it's themes and characters help inform the kind of adult you grow into. However, you start to see the art you love go down a different path, sometimes a bad one, and you can't help but feel like that thing you loved and obsessed over no longer holds a special place in your heart and it makes you lash out in anger.
However, no piece of art that you love to death is worth harassing someone or threatening them or their family with bodily harm. You must remember that there are actual human beings behind the art we enjoy and don't deserve that treatment. People make art and any piece of art has the capacity to be good or bad, because that judgement call falls to the individual that absorbs a piece of art. Art, as they say, is subjective and each piece varies in quality from person to person.
What you hate might be loved by another, and vice versa. Opinions vary and we should all learn to respect those differing opinions, within reason of course. Over the last few years, the internet has hyper-charged passions surrounding video games and film, but we all need to learn to take a step back from our passions and see the effect some of the more negative aspects of fandom has on real flesh and blood people. If we allow fandom to toxify to this extreme, nobody would want to make art at all so they can avoid having to deal with things as severe as death threats and harassment. That's not a world anyone wants to live in.