Social Democrats. The Partida Socialista is socialist in name only

No, it's completely different.
In most eastern bloc countries, communism is often associated with external oppression.
In Spain, fascism was a local phenomenon and the current democracy comes from a voluntary transition from fascism, so there has never been a purge of fascism in Spain.
Even today there are lots of pro-fascists in major political parties, and there is a not small amount of nostalgia.
I would say, generally, the feeling in Spain about fascism is comparable to the feeling in Russia about the USSR.
Obviously there is also a strong anti fascist movement, but in lots of big cities it's not strange to see fascist flags on some people's balconies.