Typically the spin and the big headlines have gotten in the way of the actualy story
First of all it is NOT a new law- blasphemy has always been illegal in the Rep. of Ireland (since the first constitution in 1937), back then it was used to protect all forms of Christianity (protestant, catholic etc). This was actually progressive at the time as it showed that protestants would be as protected in the republic as catholics (given all the sectarian violence which preceded the independance of Ireland) and the fear that Northen Irish protestants had of the Republic
This law pretty much went unnoticed for decades as nobody ever used it.
The problems arose when atheists recently wanted it removed from the constituion. Now that in itself is not a bad thing but in Ireland we have to have a national referendum in order to change any law in the constitution. Our lawmakers/ministers are not allowed to change any part of the constitution without the vote of the people (A very democratic view Im sure you'll agree). They are however allowed to refom laws- i.e. update them.
So the Minister for Justice had 2 options; spend millions on a referendum for a law that most Irish people had never heard of, let alone ever used, or reform the law.
In the current financial climate and based on the fact that nobody uses this law it was deemed better to simply reform it.
A person must publish material which has the express intent of causing outrage and offense to a religion and get that reaction- thats act + reaction + intent- which is almost impossible to prove.
Therefore the Irish government has simply updated the law to include all religions and worded it in such a way that it is practically impossible to convict somebody of it.
So its basically a backdoor way to neutralize the law without the bother and expense of a national referendum
Secondly - the catholic vs protestant killing spree over the last 60 years has pretty much NOTHING to do with religion, it was just a handy way of declaring which side you were on
Stay classy Headline swallowing reactionaries