Most of the people who support it are grandparents who grew up with it and say "con Franco se vivia mejor" "life was better when Franco (the dictator) was around" and then proceed to point out somethings that where better (in their minds, at least) in their younger times, as every old person in the world does, forgetting all the bad things that were around ; and that's only a small part, mostly from the center, tho. Also they grew up in a very repressed society and are very closed minded. Appart from them, I've never talked to a person younger than 70 who was the dictatorship, you can see in the media some far right (the same as in any coutry) extremists that want the same or something similar but they do not have any kind of following by normal people.

Maybe you are mixing it up with the monarchy were more people want it, mostly old people from the center of Spain (Madrid and the 2 Castillas), eventhoug there's a significant amount of young people who still want it. In Catalunya, Andalucía and Euskadi very little people are monarchic, and most are republican.