My understanding (from my Spanish SIL) is that Zapatero's father is or was an influential Mason, which partly explains the extreme anti-Catholic actions. The Masonic movement in Spain is very unlike that in the USA. They were the group most responsible for the civil war era church desecrations, priest and nun killings, and general church hostilities. They have always (in the past century, at least) allied with the left.
The Masonic movement was deeply underground throughout the Franco era, for obvious reasons, but it came back to life quickly once Spain went democratic.