You seem to have misclassified the causes of a number of civil wars.
In fact, all the examples you gave are examples of Marxist takeovers or attempted takeovers of government. These people always pretend to be on the side of the poor, but the people they say they are helping always end up starving to death while the Marxist leadership eats well.
In the case of the American Civil War, it was well understood at the time that it had nothing to do with slavery. Union war memorials frequently mention "preserving the union" but rarely say a word about slavery. It was about northern industrialists and Marxists conspiring to force the southern states to fund their activities. When the southern states seceded because they did not like being robbed, the industrialists and Marxists rallied their thugs to force the southern states into compliance - and by dint of their large numbers, including many socialists who had immigrated to the United States after the failed socialist revolutions in Europe in 1848, they managed to overwhelm their victims. Not only were many Union generals veterans of the socialist revolutions of 1848, but several highly placed members of Union leadership, such as Charles A. Dana, were personal friends of Karl Marx.
Among those who publicly denounced the war, and who asserted that the northern claim about ending slavery was bollocks, were the abolitionist Lysander Spooner and the British author and early advocate for the poor, Charles Dickens. The latter had just toured the United States shortly before the war, and knew whereof he was speaking.
When those Union soldiers went to the southern states - how did they treat the slaves they were supposedly liberating? Well, records from former slaves themselves record that they often tortured slaves in order to get them to tell them where any valuables were hidden. Then they stole or destroyed everything they could find, including all the food on hand, all the livestock, and all the tools with which the slaves could produce more food. They often tore mothers and fathers away from their children, and forced them to labor on the soldier's behalf - while leaving the children without any means of support. These soldiers were under orders to do most of this.
The result, as can be easily ascertained, was that at least tens of thousands - perhaps hundreds of thousands - of slaves perished from starvation, exposure, or disease that flourished under the harsh conditions they were forced to live under, during or shortly after the war.
So, for a civil war to start from the bottom up, the people must be near starvation - but for well-connected persons desirous of seizing power for themselves? It takes very little.