Censor.

It had never occurred to me writing a science fiction story could become a life threatening activity.
There is a fine line that separates acceptable ideas and to make matters worse over time the general public views change.

It is interesting how Star Trek grew from a pilot episode to an ever expanding audience and Dr Who soldiers on with a countless list of actors playing the lead.

Sometimes an author may decide to kill of their hero something like Sir Arthur Conan Doyle did with Sherlock Holmes. Although he did not suffer the repercussions as depicted in Misery
where the author was kept hostage until he rewrote the plot to satisfy a demented fan.

There are certain areas like Salman Rushdie found can antagonise the public.

In fact sometimes banning a book may cause it to become a best seller regardless of its literary content.