John, If you don't care then why are you taking the pains of writing here. Just buzz off. You will do everyone a favor.
One thing I try to do is not brag after writing complete lies and later claim -- "I don't care about the details".
The division happened long before Imam Hussein was killed and FYI you stand corrected again. It was created by Abdullah ibn Saba and his conspirators, but I think it will be too much detail for you, the one who constantly writes concocted facts.
If two groups keep fighting how does it become a shame on Islam? If two folks in a household keep fighting, then does it become shameful on the father. Apply some thought before you write again. So if Catholics and protestants kill each other as they have done in Northern Ireland, then is it a shame on Christianity?
Islam is the greatest unifying force. History is testimony to it. It unified the ever fighting tribes and low lives into a vibrant and cohesive unit, the likes of which the world never saw before, nor will it see again. Not only there was no difference between Arabs, but the difference between Arabs and non-Arabs was eradicated. the lives of non-Arab companions of Holy Prophet(PBUH) are good examples. Bilal, Suhaib-Ar-rumi, Salman-Al fari(May Allah be pleased with all of them).
What sunnis think about Shiites and what shiites think about sunnis is out of your league, but one thing is for sure, you pretend to be an atheist, but you belong the fan club of pat robertson and likes. Well it gives a nice cover to people like you to stand behind the veil of atheism and attack Islam.. faithfreedom.org is one such site. It is run by christian missionaries.