The Internet is toxic in a way that old fanzine culture and fandoms — comics fans, science fiction fans — in those days, was not. There were disagreements. There were feuds, but nothing like the madness that you see on the internet.
George R. R. Martin
When I worked at Paramount, I met with the producers of Star Trek. They were often frustrated with some of the fans. The producers invested lots of talent and money into their shows, and some of the superfans would complain about the shows, being hypercritical, declaring outrage at the slightest (or grossest) imperfections. The superfans saw themselves as The True Defenders of the Canon, and they looked upon the producers as usurpers and traitors.
There are not enough trekkies to justify the production of Star Trek movies and serieses. The continuing of the mission depends on general audiences watching the shows too. But when they hear the people that the shows were made for complaining that the shows are terrible, they are likely to stay away.
We saw a similar thing happen to George Lucas and the prequels. The films were not perfect, but they were a lot of fun. What George lacked in dialog and plotting, he more than made up for in world building. The superfans sat through many screenings of all of the films, carefully chronicling all of the mistakes, real and imagined. Star Wars was popular enough that that toxic behavior didn't hurt the business, but it did drive George into early retirement.
This has gotten much worse with social media and YouTube. The superfans now have a much louder voice, greater influence, and the illusion of greater numbers. They are parasites, gaining fame and income by attacking the work of more talented people.
They have been especially vicious to the show runners of Game of Thrones. The superfans held the show to ridiculously high standards, and were merciless when the show failed to meet them. For example, they complained about the presence of plot armor, that the key characters could be expected to survive a dangerous situation because the plot demands it. They claimed that use of plot armor is a sign of very bad writing. They ignored the fact that this show killed off main characters at an unprecedented rate. This standard has not been applied to anything else. Does James Bond have plot armor? Do the Avengers have plot armor?
Game of Thrones is the best series in the history of television, but the superfans have detailed arguments for why the show runners are the worst writers in history. The superfans are wrong. The writing on the show was brilliant. That is why a twisted epic fantasy became one of the most watched shows in the world for eight seasons.
I am really enjoying J. K. Rowling's Fantastic Beast movies. The superfans hate them. But they don't hate them enough to not see them. They will see the films, possibly multiple times, and then loudly insist that they were somehow (magically) victimized by the experience, warning the muggles to not see the films. But if the muggles don't go, there will be no more movies.