When I was in Malaysia, I saw a huge mix of hijab, full burqa and that weird metal cross veil. The woman who owned our hostel was Muslim, but she wore no head covering even though she was celebrating Ramadan.

Honestly Malaysia is a weird example to pick, since it's a huge mix of East Asian Muslims, Tamili Indians. It's also influenced by the demographic immediately to the South in Singapore, which includes those two plus a lot of Mandarin Chinese and westerners.

As far as the original question, I think a lot of people believe Islam grew directly out of a culture of war. In fact many Muslims today believe that, with belief in the prophet Mohamed being instrumental in the rise of the Arab caliphates that washed over Constantinople ~630 AD.

Tom Holland has an amazing documentary called Islam, The Untold Story: https://www.youtube.com/watch?v=K2JdTrZO1To

The Tom Holland view is that many of the Arabs in the rise of the great Caliphates didn't know about or worship Mohamed; their religious beliefs varying with many different faiths, and even embracing some of the Yahweh/Judaic faiths in the region. The story of Mohamed was added later to solidify empires.

In so many ways, it's very similar to Constantine and the birth of modern Christianity: faiths use to solidify a State, Kingdom or Government.

The modern cultures of Islam, just like modern Christianity, would be unrecognizable to the people of those faiths centuries ago. Christianity has become much more secular, and the Sam Harris of the world (not a fan; he's a retarded fuck, but sometimes has good points) hold the conflicting beliefs that Islam is "The mother-load of bad ideas" while simultaneously believing it can be tamed and made secular (in his 2015 book Islam and the Future of Tolerance).

Religions are just a coaster; embraced to grant legitimacy to states and altered throughout the centuries to fit the current moralities. All of today's faiths, if they exist 200 years from now, would be unrecognizable to us.