Please forgive my ignorance. However, I would like to learn.
Can anyone explain to me in general terms, say one paragraph, why do Sunni Muslims and Shia Muslims hate each other?
I’m not an expert in the history of the ME by any means, but I believe it all stems from a fight over leadership of Islam following the death of Mohammed. I can’t remember which was which, but either the Sunnis or Shiites believed that the next caliph after Mohammed should be a member of his family and the other group backed someone else as caliph. There may be other doctrinal differences, but I believe that was the root of it all.
When the prophet Mohammad died, he had not named a successor. So, his Muslim followers were ripped apart by which successor to support: 1) Mohammed’s brother-in-law or 2) his uncle. Neither side has conceded and so there's been 1,400 years of war between the two factions. There have been other sects of Islam, but they have all split along the Sunni vs. Shi'ite division.
The war continues in Syria. Assad's tribe is the Alawite Muslims that are supported by Shi'ite Muslims, Druze Muslims, and Christians. They are 26% of the population that run Syria. The rebels are predominately Sunni Muslims, as are 74% of the country. They are backed by the Saudis (Sunni) and Assad is backed by Iran (Shi'ite). That's the story in a nut shell. There are no good guys here; there are bad guys and worse guys. They are all murders and thugs.
When deprived of a sufficient number of Jews or infidels to kill, Muslims satisfy their blood lust by killing other Muslims.