Books have changes a lot over the ages of man. In earlier parts of time books mainly consisted of religious content. In fact, they were the most sought after books during that time. Now the most sought after book is 50 shades of grey. In that time books main reason for existing was for purely for education. People read books back only so they could gain knowledge and only to interoperate the bible for themselves. Now people use books for pure entertainment with topics like romance, action, drama, and sex. Books these days have just become yet another way to entertain the masses; and do not think they will be changing back anytime soon because in this day in age knowledge does not sell like use too.
Our freedom has come a long way since then we can write about just about anything this day in age, from politics to religion and marriage. People use the freedom of press to express their views on every, even if some people abuse it.