It's hard to believe that such a law would pass, but let me point out that the Act is not exactly what it seems. (Yes, I'm Irish)
The Law Reform Commission - the people who are charged with updating legislation in Ireland, recommended that a law had to be put in place for blasphemy because it was provided for in the constitution.
They also said it didn't have to be done any time soon, and that a referendum would remove the requirement. The Irish government is very touchy at the moment about holding any additional referenda (especially in light of an upcoming referendum that affects all 27 EU members), so it decided to pass a law.
People - from the left, the right and the centre - all let out a collective 'gasp!' of surprise. The man responsible probably thinks he has been clever.
You see, what has actually transpired is not so much a 'blasphemy law' but a law that is unenforceable. The law, as written, cannot be used in the courts.... and deliberately so.
It's an Irish solution to an Irish problem: We need a law if the article remains in the constitution. The constitution won't be changed, so the article will remain. However, the crime is outdated and we actually do not want anybody to be charged under this law. Therefore, the only remaining choice is to draft a law that is unworkable.
Is it's a silly, high-cost manoeuvre? Yes.
But it's a tried and tested method.
Why it was rushed through is anyones guess - a mixture of pandering to a far-right that may not currently exist in Ireland (but one suspects is probably going to gain ground in recession times), a particular individual trying to score a quick victory or just an ill thought out move.
Some of our politicians are quite slow to recognise the obvious and will latch on to an idea.