The idea of copyright did not exist in ancient times, when authors frequently copied other authors at length in works of non-fiction. This practice was useful, and is the only way many authors' works have survived even in part.
No person, no idea, and no religion deserves to be illegal to insult, not even the Church of Emacs.
Control over the use of one's ideas really constitutes control over other people's lives; and it is usually used to make their lives more difficult.
The idea that laws decide what is right or wrong is mistaken in general. Laws are, at their best, an attempt to achieve justice; to say that laws define justice or ethical conduct is turning things upside down.
Odious ideas are not entitled to hide from criticism behind the human shield of their believers feelings.