If ever Muslim societies became secular, I would still expect their culture to reflect their long history of Islam, in their official holidays, their expressions, their art and music, etc. 

Secularism does not mean pulling your culture out by the roots to reform it. The French Revolution and the Soviets and the Chinese Cultural Revolution tried that, with disastrous results. ISIS is doing its own cultural cleansing" by destroying those monuments which predate Islam.

That is destructive and unnecessary. The French don't need to destroy Notre-Dame and all evidence of Christianity from their culture to have a secular society, any more than Turkey needed to destroy all its mosques, art and music.

Xmas is now a fun holiday people all over the world enjoy for what it is today, with little understanding of its religious roots. Even in Pakistan!

http://www.nbcnews.com/news/world/christmas-big-hit-islamic-republic-pakistan-n270666