Because strict literalism and black and white thinking are more common than people like to admit.[/QUOTp
That's quite a passive aggressive dig.
I submit to you that it isn't black and white thinking. Having watched Star Trek from the first season of TOS. I was hooked at age 11. At the end of season two, I wrote to the network, one of many thousands who did, to urge the network to renew the series. I went to conventions in the early 70s and 80s, and bought every early fanzine I could find, and had a few boxes of them by the time I was 14. During the long period between the end of TOS and the first movie, fans like us kept the flame alive by attendance at cons and fan activities, and supported the creators with a built in audience for their hopeful future productions. If no one showed any interest, Star Trek would not have continued with a "franchise".
During that time, much of the writing in those zines, etc., and the editors thereof, were careful to follow canon or they would label their zines etc., AU, for alternate universe. A lot of that writing was far superior to what later series creators splashed against the wall, ignoring canon because they were too lazy to familiarize themselves with it, weren't familiar with the series, thought it was campy or bad, and didn't bother to learn what they were supposedly continuing.
Now did the owners of Star Trek have the right to do this? Sure they did. Regardless of the support for the series that allowed the continuation of it to become a "franchise", they owed the fans nothing. We got our own satisfaction from our activities. But where they disrespected or dishonored the series in their later productions, it is supremely egotistical for them, showrunners or later fans, to expect TOS fans to swallow whatever sloppy mess was thrown over the wall regardless of what had been established before. Star Trek became a valuable property in part because of the built in audience that comes from the prior canon. And there's a lot of hubris and stupidity in hating the fanbase because not everyone laps up whatever they produce, whether it follows canon or not, especially those that took a direct shot at the original fanbase in disrespecting TOS and its canon, or who thought that a bigger budget gave them license to change it. Why not create new shows if they can't be bothered or have so much hubris, they believe they can improve Star Trek by retconning the past. But then they wouldn't have that built in audience would they? Or be able to deliberately disappoint the expectations of the fanbase to show their disrespect.
Again, do show runners or movie producers have the right to do this? Sure they do. But some fans recognize laziness, indifference, hubris, gilding the lily because the have the budget to do soregardless of whether it starts to become ludicrous, or down right spitting in the eye of those fans whose dollars they expect to collect for their endeavors, even as they disrespect the very material they are trying to capitalize on.
It's sure not black and white. Or devotion to strict literalism. That's shallow thinking.