Let me explain, in a roundabout way.
I've read plenty about the recent Ben Affleck and Reza Aslan vs Bill Maher dustup on Maher's show.
I've also read several of my online atheist friends see this as not only an easy opportunity to take a quick shot at Aslan, as here, but also to write off Affleck and at least partially support Maher.
First, this is Bill Maher the antivaxxer, etc. Atheists who claim to be skeptically-minded in general should continue to do so.
Second, Aslan, and Affleck, aren't all wrong. And, yes, I recognize above, that I'm arguing with a former Muslim cum atheist.
That said, my thoughts have gotten more guidance from Christopher Catherwood, a British scholar of religion, in his book, "Making War in teh Name of God."
He notes that many modern Muslims, primarily those living in the "West," outside the Dar al-Islam, do work to make Islam a religion of peace, and jihad an internal struggle against wrong ideas, motives, etc. Thus, for them, Islam IS a religion of peace. And, even if they're not a majority of Muslims in teh Dar al-Harb (traditional), or Dar al-Salaam (their alternative), they're at least a substantial minority.
Of course, in the Islamic heartland, it's different. At the same time, there are more liberal-minded Muslims inside the Dar al-Islam, even if a small minority. (I'm counting most rulers of states in the Muslim Middle East as being halfway secularized, and neither religiously conservative nor religiously liberal.)
For many of those Muslims, jihad is war against the infidel and Islam is, to the degree we focus in jihad, at least, a religion of war.
However, three other things pop in mind.
Two are my own.
Many liberal Christians say that Christianity is a religion of tolerance. They sincerely believe that, and, by and large, within their slice of Christianity, they're right. But, in the US at least, the majority of Christians is at least somewhat, if not fairly largely, intolerant.
How one falls on working to parse this issue is in part related to how much of a Gnu Atheist a particular atheist is. So, that too is cautionary for atheists ... at least those who don't want to be Gnu Atheists. If you do, well, I guess you can go ahead and stop reading.
Second is that, just as there is a larger, social and cultural, Islamism pushed by Islamists, there is a larger Christianism pushed by social Christianists such as Samuel Huntington, Bernard Lewis and Rodney Stark. And, while their may be a large gap between the US and Old Europe in terms of active, believing Christians, there's not nearly as much of a gap on the two sides of the pond on Christianism. Let's not forget that former French President Jacques Chirac said, several years ago, that Turkey should not be admitted to the European Union because it doesn't have a Christian heritage.
Third comes from Catherwood.
He notes that "church-state issues" have always had a different history in Islam than in Christianity. With his marriage to Khadija, Muhammad thrust himself into tribal-level politics at the start of Islam. The Umayyads headed one of Mecca's tribes. And, until the creation of Ataturk's Turkey, Islam had nearly 1,300 years of ... caesaropapism or whatever you call it.
Two other notes, also via Catherwood, with my spinoff on the second.
One is that both Islam and Christianity have, over the centuries, fought internecine religious wars, as well.
The other is that non-monotheistic religions (though his book covers just that), like fundamentalist Hindus, have also fought religions wars.
And, while I'm not far enough into his book to read about the third monotheism, Jews should remember that the ancestors of Herod the Great were converted at the point of a sword.