Name one country where there is no religion? That's like saying air is the leading cause of death because nearly everyone who has ever died was breathing air at the time of death.
You are highlighting true issues with how people use their religious power. However, you are ignoring the countless others who are happy in that same extreme living space or in the much larger world where extremism is not law. Its called cherry picking.
The OP was not requesting opinions on cherry picked scenarios. When you break down plausibility for humanity impacting crisis', an event rising from AI, genetic manipulations, or otherwise have a far higher possibility than tyrannical religion. Fact is, we already have and have had extremist religions powers. Humanity hasn't been threatened.
Hell, what has threatened humanity? WW1 and 2. The Cuban Missile Crisis. Those had nothing to do with religion but power and that power utilized weapons and scientific studies to kill millions. Especially during WW2.
It's far more likely that we're going to see a plague caused by genetic manipulation.
It's far more likely that we're going to have issues from AI.
It's far more likely that we're going to become to reliant on science / tech and when it collapses from some war action, we'll all be screwed. (read the one second after book, good stuff)
Now, don't get me wrong. I love tech and science. I can't wait to see implementations of self driving cars (I'm buying a Telsa later this year). I will be among the first to sign up for nano-tech injected into my body as a better immune system. I am un-trustworthy of GMO food in general (another topic I see as a big risk to humanity) but I'm not against further study on producing better food genetically. (difference is in injecting poisons vs increasing size/nutrients)
The argument isn't which one is better than the other as both have merits and risks. This isn't an emotional discussion. But which has the most plausibility to be a threat to humanity. Organized belief in a god is actually on the decline WW. This is why there is so much backlash in America as Christians are now becoming more and more extremist. Its a defense mechanism. (btw, I'm not atheist or Christian) But, mistakes in several scientific fields simply have a higher plausibility of happening than a large-scale religious based conflict or a religions based terror group attempting to kill us all off with nukes/virus/etc.
I think you missed the point. In WWI and in WW2 religion played a part. It was very prevalent in WW2 considering Hitler was targeting Jews. The point however is that much like politics with two sides opposing, religion is much of the same with an even more dangerous narrative. Religion is used in every culture as a way to control people and create a hive type mind. Make everyone fear a "God" and do his bidding so that anyone in a position of authority in said religion controls the masses. Back when religion was invented it was an ingenious way for a different class of people to gain power by manipulating people into belief based on "miracles" and scare tactics. Why people still believe in these fairy tales is beyond me but it is having the same effect now. People are radicalizing because it gives them purpose where they have none. It makes them important in their heads and gives their life meaning. That is very dangerous as it gives reason to do unspeakable things in the name of your religion and for people on the edge is an enabler.