At first, as non-native english speaker I don't know what's the right english word for 'Rahmat'.
Scholar in my country always says "Difference is Rahmat". And I'm totaly agree. There are some difference between a Muslim and another Muslim but that is not a reason for fight or call Kafir to another, and that is not a reason for cursing some persons in Islam.
Unfortunately, not every Muslim can accept those difference. You can count how many Iraqi people were killed in battle against US military and their ally, and how many Iraqi people were killed in sectarian attack. That's really make me sad, and case like that not only happened in Iraq, also in Pakistan.
I hope they will realize, if united Islam stands, if divided Islam falls. And I hope one day all Muslims will unity. When we have unity, we can solve all problems in Islam and we can build a better future for ummah.