The Spanish people voted yes to democracy, not to the constitution. The communist party supported it because it feared continuing to be illegal otherwise, and it is an issue that still causes them a lot of division.
My generation did not vote for the constitution, and many of us dislike it. I agree that it is a conservative constitution made out of fear, with a flawed electoral system, a king, etc. The same fear that the party in power, lineage of the dictators, uses to address our aging population.
"Mejor malo conocido que bueno por conocer" (Better a known bad than the good that is jet to be known) is the worst Spanish saying.
I am Andalusian and pro-referendum.