Let's see, before Franco invaded the Republicans were executing priests and monks, raping and murdering nuns, looting churches, taking over private businesses and in imprisoning the owners and managers.
Then Franco's troops invaded and began to systematically execute all mayors, town councilmen, union leaders, anybody who was denounced by anybody who owned a blue shirt (Spanish blood feuds can go back a long time) and oh yes, almost of anybody they captured who had a bruise on their right shoulder.
Good guys? What good guys.
When you have Communists fighting Fascists, who do you root for? Nobody. However, most of the loyalists were not Communists (despite the fact that Communists eventually took over the movement), and many of the rebels weren’t fascists. Atrocities abounded on all sides.