Salaam,
Wrong. The love of God is the foundation of this religion.
Also more wrong, the Sunni and Shia were fighting was over power and dominion, as man has done for all ages and not over following the Quran alone or not. If they followed the Quran as it is taught there would never have been so crude treatment of Hussein and his family. The Quran teaches how to be a righteous person and that very well too.
I have studied this problem a bit and I suspect that the first followers of the prophet were righteous men although I am not sure about it after the massacre at Karbala.
Ali and company's adversaries tried to pervert the religion in various ways, but how we do not know except rumors. I have heard that they tried to change the Quran and that the original transcript was burned.
The enemies of God got in motion as soon as Muhammad died and forgot everything that the revelation had taught about behavior and good deeds. All transformed into a fight for power instead of being humble.
As much as I know Ali accepted (unwillingly or willingly I do not know) that he did not become the first caliph. If historical documents are right and not seriously biased I do not know though.
The Sunni side with these guys had nothing to do with religion. They were just after power and were enemies of God. Ruling the early "ummah" probably meant much wealth and fame.
You need to remember that the majority of people are not believers. This means most people, even Uthman, Omar or other people back then were likely victims to greed and arrogance. I am not ruling out descendants of the prophet too. Bloodline has nothing to do with being righteous or not. When Ibrahim asked if God's covenant would cover his offspring God replied that His covenant does not cover the unrighteous. It is easy to conclude that it means bloodline has nothing to do with righteousness although the knowledge that may be transferred from father to son may give him an advantage, but it then depends on this individual.
All of Jacob's sons were not righteous, despite being his offspring.
In conclusion; the following conflict after Muhammad's demise was only due to the shortcomings of man, greed and selfishness. You had what you needed from the Quran that just had been finished. But very few people followed the Message from God and it remains the same today. Very few follow the Message without extra-religious teachings or assigning partners with God, as you do according to your last post were you said the foundation of Islam is to love the prophet and family.
God bless you