Diversity of opinion within the framework of the Western Enlightenment is fine. In science we encourage diversity of opinion at the hedge of our knowledge.

But if you tell me that your book, say the Koran, says that salt and water do not mix, then take your book and get out of my country. We do not need diversity when it comes to equality of opportunity between  male and female; or when it comes to genital mutilation.

We do not need racial or cultural diversity per se. We need free speech which is the mechanism by which real diversity helps up progress.