I saw the exact same comment, no that's a very weak argument. Let's reductio ad absurdo: 200 years of Christianity is nowhere near the same as 200 years of Christianity. One was in the midst of persecution but growing strength in minorities the other was entering its golden age. 1100 years into Christanity it was at its cultural high point, unlike the year 1700 in Islam. Also if this were true considering Hinduism has been around much longer than Christianity we would have the whole history of Christian and violence already mapped out.

But let's treat this argument charitably instead: violence emerges because religion has to undergo "growing pains". It's a nice teleological argument but i really don't see it working. Non adolescent religions like Buddhism are committing violence in say Burma and [Modi's Gujarat] ( http://www.nytimes.com/2014/04/19/opinion/being-muslim-under-narendra-modi.html?_r=0) was hardly a early Hindu society. For that matter it's actually a pretty insulting claim to say that Islam isn't a developed religion given its history of religious thought and movements. Rather the problem has to do with our conception of religion. we conceive religion as a separate and removed sphere of life apart from culture while in reality such hard distinctions cannot exist. and we have an overly intellectualized definition of religion.

Armstrong has a recent book out which looks interesting.

eover, the idea that belief is central in religion makes sense only when religion means having a creed. Until the British started classifying the people of the Indian subcontinent by their religious affiliations, Armstrong points out, there was no such thing as “Hinduism.” Instead there was an unfathomably rich diversity of practices, which weren’t seen as separate from one another or from the rest of life, and didn’t define themselves in terms of belief. The same was true in pre-Christian Europe. “Neither the Greeks nor the Romans,” Armstrong reminds us, “ever separated religion from secular life. They would not have understood our modern conception of ‘religion.’ They had no authoritative scriptures, no compulsory beliefs, no distinct clergy and no obligatory ethical rules.”

First, through most of human history, people have chosen to intertwine religion with all their other activities, including, notably, how they are governed. ...because people wanted to endow everything they did with significance.”Second, this involvement with politics means that religions have often been tied up with violence"

To understand why religion is often violent you need to understand the entire cultural ecosystem. Tamiyyah wouldn't have penned his defense of calling other muslims takfir and thus able to be warred against if the Mongols hadn't sacked Baghdad, the current growth of Islamic radicalism wouldn't have happened if Islamic societies in the Middle East hadn't been so despotic and if Arab nationalism had succeeded instead of failing economically and politically (defeats of Israel),* Hindu nationalism wouldn't exist in real a toxic form if imported to a society with a less diverse population, Sudanese religious violence wouldn't happen if there wasn't a pre existing problematic racial-cultural and religious splits in the population.

this isn't to say these things cause religious violence, rather religious violence acts in concert with this stuff and tendencies towards violence can be exasperated or minimized based on the culture and politics of a society as a whole (it's why for instance Christianity doesn't have a modern violence problem)

*and this is ignoring deeply contingent acts such as the specific actions of the House of Saud and Saudi citizens.

That being said a limited version of the claim may perhaps be true: after insanely bloody times society reforms itself to protect itself from religious violence. That's what happened to Europe as a result of the 30 years war (look at the data on deaths in Germany, it's horrifying). So perhaps if islamic societies embark on nuclear war style annihilation they will be essentially forced to radically change Islam but that sort of argument presupposes certain types of acts need to happen and such events seem contingent to me.

http://www.nytimes.com/2014/12/14/books/review/fields-of-blood-by-karen-armstrong.html

http://www.newrepublic.com/article/119698/religion-not-blame-all-bloodiest-wars

edit: i've often switched between religion and islam because that's the key subtext of most of these claims