On the ground, especially in areas like Kerry & west cork which were not part of the ( relatively) large scale civil war fighting ( which occurred in Dublin and latter on the fractured front line of Limerick city, limerick county( where the closest thing Ireland has ever seen to modern open, battles ocurred after the fall of the city) and mid munster) the fighting was bitter because so little divided the combatants, they were known to each other and the fighting was small scale, small unit based on both sides.It was almost inter parish rivalry writ in blood.
At a more senior level within the pre-treaty movement there was a more fundamental disagreement , though here again little other than personal affiliation of the minority of leaders who went pro treaty to collins & mulcahy was often at the heart of the decision of combatants either way.
The divide referred to above in the earlier post was not one , in my view , that directly drove the combatants drawn from the pre-treaty movement.
This is because any real 'haves" ( in terms of world view rather than just net worth or background) were on the periphery of the fighting. They were either found on the political fringes of the movement ( e.g. kevin o'higgins) or in the form of those bankrolling the "national army" or filling its ranks in the form of ex. B.A commissioned officers.
the counter revolution got going in the vacuum created by the fighting, the latter having sucked in those committed to an independent different ireland. I am not one who subscribes to the lost leader or lost republic fantasy. But as per the above mentioned o'higgins and his sorry cabal the clongowes boys got their feet under the tables a hell of lot quicker thanks to the civil war than they would have otherwise.
And the fuppers, their seed & breed , ilk , hangers-on and mimicers are still running the stinking place today.