Ofcourse if we dig deeper, US and Israel have their hands in much of this. Sunni-Shia conflict serves their interests, they opened the pandora box in Iraq, then Syria.
Iraq maybe, but dude U.S didn't have much role in Syrian uprising. It seems for most of you guys any middle eastern/Muslim/developing country can't have an uprising or people being fed up and rising up against their tyrants without them being labelled U.S/Israeli agents. LOL I am 100% sure that if one day people in Saudi Arabia also rise up against their leaders then they will be labelled U.S/Western agents and people will use all sorts of conspiracy to justify their claim. lol
Don't get me wrong, other foreign powers might get involve to secure their interests during or after such uprisings but saying they are the origin/cause of that belittles the blood sacrifice the common people of that country made to get rid of their tyrants. What will you say about Mubarak of Egypt, Ben Ali of Tunisia, Qaddafi of Libya or Saleh of Yemen etc where their people rising up in mass against them all caused by U.S/Israeli agents as well? lol I would have also added Bahrain if not KSA helping them crush the people's uprising there as well(just like Iran is doing in Syria. lol ).
So you guys should also look at things from another perspective and recognise that others also have their grievances and other countries (not just western powers) also have their own interests.
I think we have to acknowledge that blame is on both sides, those who want apocalyptic war between Muslims are agents of Kuffar.
That's the main issue with most countries in the region. They see religion in everything. Geo politics is not always about religion. So stop seeing things from a religious perspectives always, else you will not often see the bigger picture and will often misread the situation or other countries intentions/interests.
The moment you start seeing things from a religious perspective only(especially in politics) then you are on the wrong footing. Politicians(even those in region) are only after their own selfish interests, they merely use religion to fool the gullible masses who they know are quite religious focused and thus emotional to religious slogans/sweet talk. In fact there is nothing better for such politicians than a religiously focused and obsessed population, since they don't even need much effort to cover their incompetence/corruption/nepotism/sectarianism/bad governance and bad leadership, they only need to use religion to make the people overlook their failures and divert their attention from these issues. So it's always good to leave religion aside and judge things from a more rational perspective.
For one Russia is not Assad's main ally because of their love for Syria or Assad. lol If anything Russia is even more christian than most western countries. So it's all about interests. Every country in the region as well is after their own interests. There is nothing like supporting the other because of Muslim or religious brotherhood. Else Turkey and Iran wont be on opposite sides in Syria, Iran and KSA wont be mortal enemies and using the people of the region to fight their proxy wars to the last man there, Egypt and Turkey won't be on opposite side of almost everything, Pakistan wont be closest of allies with super atheist pork eating China meanwhile Pakistan and Bangladesh don't see eye to eye per se etc etc.
So religion has little to do with geo politics nowadays.