I'm interested to know why sectarian conflict so often involves Muslims. Is it geo-political, sociocultural, economic, or is Islam fundamentally more intolerant of other religions than those it finds conflict with? I realise historically all religions have clashed ideologically, but what is it about the recent climate that has led Islam to fight battles on three fronts in a time when other sectarian conflicts have eased into an era of relative acceptance, tolerance and cohabitation.
I am not speaking for the Hinduism of which I know little. Although I suggest you type "Hinduism clash on other religions", and investigate more the notion of Hindutva (purely Hindu nation) and how they clashed with Christian in particular. Buddhist extremists also massacred Muslim minorities recently, you can find more about it on Google.
With regards to Jewish extremism, a google search can also help. With regards to Christians, let's be serious for a second and look at the US and the recent declarations of some politicians and their numerous followers.
No there is no "inherent" Muslim intolerance. Although, yes, Islam, like many religions, rejects other religions.
Regarding your question: "why now". That's what matters. I am not a specialist, I can only point to numerous books (like Faith and Power, The True Story of Radical Islam, etc).
But just food for thought: any religion, any doctrine, any political idea, can serve to fuel radicalism. A great quote by Olivier Roy says "it is not radicalisation of Islam, it is Islamisation of radicalisation" (bad translation from French). Why Islam, why now ? Because it just so happens that the part of the world that was repeatedly attacked and plundered in recent history (middle east, parts of Africa) has Islam for main religion. That prevented the natural evolution of nations towards democracy and cultural flourishing. In some cases, even well developed countries were thrown back into the dark ages. Take Libya, a very stable state with healthcare for all and one amongst the highest education levels in Africa. Now torn apart.
When education is low, people turn to the one common idea they have, and it is usually religion. That happened in Algeria with the 10 years long civil war and 19 years long state of emergency. What was very weird in Algeria was how it unravelled: the country was a dictatorship with one party, the day free elections were held, people voted for the Islamic party overwhelmingly. A party whose part of the program was "vote for us, we will get rid of democracy and replace it with an Islamic state". What people often forget is that Algerian voted for this party in astounding proportions. This is what lack of education does. Then the military denied power to the Islamists which then became terrorists. But the people were for them in the beginning.
You can read The Moral Arc, (or watch the youtube video) on how Critical thinking and science can counteract that radicalism as it did in the past. That's what is needed in my opinion.
Science creates critical thinking, critical thinking prevents people from following blindly and being manipulated.
I can go on some more but I hope I, at least, cleared that point: yes Islam has a lot to do with what is happening, no it is not an inherent property of Islam.