There's soft guardrails for "reputable" content. A publishing house has to buy it, stores have to agree to distribute it, and if people are upset they can raise

There's soft guardrails for "reputable" content. A publishing house has to buy it, stores have to agree to distribute it, and if people are upset they can raise a stink and get the book pulled. Technically, people can write whatever they want, but practically you can't walk into a bookstore and read whatever you want.