You've probably seen a lot of stories about how fans are complaining about the movies and shows that they watched recently. You hear about how the costumes were wrong, the characters were poorly represented, the plot isn't what it's supposed to be.
But why do these complaints exist? Why do people get into such a fuss over these little things? I've got one word for you.
The reason fans complain so much is because they are devoted to the genre, whether it be Star Wars, Star Trek, Marvel, or DC, fans of all mediums can be passionate. Fans who read the comics don't like when the movies don't exactly line up with the comics, and avid movie fans don't appreciate when the comic guys start throwing their opinions out there. That is what starts the community firing shots and sniping back and forth, devolving into chaos. This makes the community a less pleasant place to be, and starts the sort of issue with online bullying.
The thing that needs to happen is that the devotion needs to be tempered. Not saying that you shouldn't be devoted to your favorite brand, but that shouldn't give you a reason to throw insults around. Instead, different opinions should be discussed, calmly and collectively, debating instead of arguing, making the community a more pleasant place for everyone.