Yes the atrocities by the Communists and those that opposed Franco we also horrible. However, the general feeling was that the Soviet Union sent those resisting Franco ship loads of weapons. Communism has clearly not worked to move Spain out of poverty, then again, the EU has also failed to move Spain out of poverty compared to other EU countries.
My perspective is that Communist ideology in terms of economic theory is not popular with the people, but that those whose grandparents fought, died, and were tortured by Frano, have a soft spot in their hearts for the image of the past Communist Party.
When you visit Spain you are struck by the three different police forces. The local or municipal police (phone 092) are controlled locally. The National Police (phone 091) are under a centralized national control and are to deal with more serious crimes. Civil Guard (phone 062) are very military in orientation and under centralized national control.
During Franco the Civil Guard and the National Police were used by that government to oppress various parts of the County. There are still strong feelings against them at times, especially in those regions (Basque, Catalonia, etc.) that think of themselves as semi-independent areas.
Franco and the Spanish Army crushed a communist controlled shell government. Franco was utterly ruthless with the left which is as it should be. Unfortunately so called democracy was restored, which means leftists take over because they, like cock roaches never really go away. In Latin nations a right wing authoritarian government is the most desirable form. We in the Us are seeing what the Spanish saw during the so-called Second Republic. Politicization of every institution and its subordination to leftwing ideology along with organized terrorism towards all opponents. Franco was one of the great men of the 20th century and the removal of his regime was a disaster for Spain.
And a funny Spaniard-talk-about-Franco anecdote. I was talking to a Spanish colleague about Spanish TV and I said I was shocked to see pretty explicit adult action on regular TV. He said 'yes, I know. I don't like it. But you see, Franco always cut movies up and now we don't want them to be cut at all. But to me I think it's bad because they show them at 11 or 12pm, when they children are watching."
Spain does things on it's own time!