If one of the reasons was that it was their religious duty to engage... Full stop. Think of it like this. If I was POTUS, I might go around giving speeches to the citizens outlining my reasons for going to war. One of those reasons could be religious conflict with those we're fighting, or even not, but at the end of all my speeches I talk about how god is on our side and will have couched the conflict in religious terms saying such things as "god has tasked our nation with defeating our enemies", or things like "It is our religious duty, if we don't do this god will pull his favor back from our nation and our society will crumble as a result", etc...
So every war when anyone has ever mentioned god in a speech to boost morale is a religious war? Is every war when anyone has mentioned family a family war? This is every war in human history pretty much.
If you want to call WW2 a religious war or count its victims as victims of religion, be my guest. It doesn't much chime with someone who claims to value reason, but each to their own
Anyway, even under these ludicrous conditions, you are still wrong. There probably haven't even been 1 billion war deaths in total in recorded history, so even if you claim 100% of war is religious because someone once mentioned god, you're still over 4 billion short.
To the point about Indians and Muslims... What is it with you and the air of condescension? Look, I'm aware that some inflation of numbers went on in the telling of the Muslim invasions into India between 800CE and 1700CE, and just because the population of India was around 100 million people that doesn't necessarily prove my point wrong.
I'm talking about waves of invasions into India territory over centuries, ie the Turks, the Afghans, . Take a look at this article about it...
Islamic Invasion Of India: The Greatest Genocide In History
The article is a load of rubbish, the title alone tells you that.
I used the Mongol period as that is widely considered the most violent (although it wasn't actually unusually violent at all).
Seeing as it makes no difference though change the 200 million deaths timescale to 1000 years. That's a millennium of warfare almost as intense as the 30 years war. A timescale during which the population increased, and the empire was famously wealthy. And after 1000 years, they were still majority Hindu.
How do you think a minority rules an empire with Hindu help for so long if they are fanatically killing as many Hindus as possible? How do you become famously wealthy if you are culling your population in a manner that ruined Europe? They are your source of income, military power, food, etc.
Anyway, as I said, and as you seemed to gloss over it... Yes, we've got the numbers on purely religious wars; WHAT WE DON'T HAVE ARE THE NUMBERS ON COLLATERAL DAMAGE.
Where does this 4 billion come from?
The highest rates of HIV are in countries with small Catholic populations like South Africa and Botswana so its hard to make a case that Catholicism is a major cause.
"How many people have died because religious teachings said that disease was caused by demons instead of germs?"
I find it pretty hard to take this seriously.
Anyway, the consensus among academic historians of science is that religion, particularly Christianity, was a major contributor to the development of modern science. The conflict hypothesis that you are promoting is a common myth, but not one believed any more by experts. But, hey, who needs experts and evidence when you've already decided on the truth, evidence be damned.
Given the role of science in medical treatment, religion might have a net positive. What about lives saved by religious charity? What about the wars prevented by religion? Anyway, still don't need these as you are over 4 billion short even having every war in recorded history as a 'religious war'
Can you make a logical case for 4 billion please?
In any event, we know with pretty good certainty just how many people have lived and died since the dawn of mankind... 100 billion people...
It is pretty safe to say that billions of people have died due to religion and religious conflicts, both the people who died as soldiers, as well as all the collateral damage civilizations incurred as a result of those conflicts.
Why is it safe? You have offered nothing but fantasy in support of you opinion.
100 billion.
20-40% of whom probably died in infancy or early childhood going by high mortality rates in ancient times.
If 25% you are saying around 1 in 15 humans who didn't die in infancy/childhood ever have died because of religion? This would probably equate to maybe 1 in 10 males.
In the industrialised slaughter of WW2, with carpet bombing of civilian populations, and modern weaponry 1 in 10 German males died.
Religion has killed men at the rate of WW2 for ever and ever? Notice another problem here?
You can't be serious, surely?