Spain was on a spending spree and now unfinished airports and planned communities that have never had a single person use them sit rotting down, the investors money gone forever.
Bad decisions have bad consequences.
It was my understanding that Spain’s (and Ireland’s) economic troubles were not the cause of socialist policies–they were not created from government debt for social welfare or military programs–both countries ran budget surpluses and maintained very very low debt to GDP ratios. Instead, their problems came from speculation in the PRIVATE sector, specifically property speculation...although borrowed euros at very low interest for massive public works also appeared to have played a significant part as you suggest.