Why is Ireland so puritanical? Watch
That's why abortion is illegal and why Playboy has only been legal in the last couple of years.
The Catholic Church was able to capitalise on Ireland's misfortunes to gain advocates. As Ireland became increasingly more wealthy, the Church began to lose it's grip.
Honestly, I don't think Ireland is as puratanical as it once was. Although I believe it still the highest Church attendance for any country in Western Europe.