I think you are correct. During the Spanish Civil War, there was not as much of a geographical division of sentiments as found during America’s Civil War. Often, rightists and leftists coexisted in the same town, though mostly in different neighborhoods. That is similar to the situation in the US today.
Of course, as the war evolved, left/right groups coalesced and people moved to the areas controlled by the side they agreed with. Often they were forced to move because of violence.
The so-called fifth columnists were rightists in Madrid supposedly helping the Nationalist forces as four columns of Franco’s army moved on the capital.
Both sides were coalitions. The Loyalist faction was made up of liberals, republicans, anti-clericals, syndicalists, anarchists, and Communists. In the end, they were betrayed by Stalin and the Communists.
The Nationalist side included monarchists (like Franco), authoritarians, clericalists, conservatives/reactionaries, and fascists. Franco is generally not considered to have been a fascist. He used the fascists for his own purposes.
And thd Spanish at least all spoke (not counting Catalan or Basque) one language, Spanish, and were all of one basic ethnic stock. Today we in the USA have a more complicated situation, with a large Spanish speaking minority in many parts of the country, and multiple races, white, black, etc. If anything, our CW could be uglier than Spain's, and that was hell on earth.