Hey Ireland would not have beaten England otherwise.
I suppose it is possible that some Catholic schools in Northern Ireland play cricket. But it would surprise me.
Why? Hindus and Muslims play cricket, sometimes in the same team.
Also, could someone explain to me the US definition of “middle class”?
The two communities tend to play different sports. Cricket is regarded as a “foreign game” in the nationalist tradition of Ireland. For many people, Gaelic games (football, camogie and hurling) are a key part of the Irish sense of identity and community. It would seem unusual if a Protestant school in the north played hurling, and equally it would seem unusual if a Catholic school played cricket, although I suppose neither is impossible.
Soccer is enjoyed by both communities, but this shared interest can also serve to divide rather than unite.
I’ve tried and failed before to describe the distinction in usage. The best I can do is that normally an American saying “middle class” means “not rich”, while a British person saying “middle class” means “not poor”.
British Middle class is approximately equivalent to upper middle class in the US. Your Professionals, lawyers, Doctors, Bankers etc. However money is not the only indicator of class in the UK.
I knew quite a few Irish Catholics who followed cricket.
Its popularity is rising south of the border and there are pockets of long held popularity throughout the republic. However, in Northern Ireland, as Hibernicus has explained there’s always the “our thing” and “their thing”, cricket being one of them.
Is Irish hurling the same as hurling that also follows heavy drinking in North America? It would be one of their national sports? 
No.
How much intermarriage was there among the upper class? I know that the man who was Chief Constable of the RUC for part of the troubles was Catholic and married to a Protestant and he had to retire to London. But was it more a case of that they would mix socially but marriage was a no no.
Which is a big pity. The Irish fans at every cricket match I have been to have without exception contributed to the atmosphere.
Hope thats changing now.
That’s your problem, there.
If he was Dr Declan O’Neill the local Catholic GP marrying Lily Brown a local Protestant dentist, no-one would bat an eyelid.
Mixed marriages in the middle classes are increasingly common.
I went to one at Christmas- the fact that it was the bride’s second marriage, and that the bride is 10 years older than the groom with 2 teenage kids was a bigger deal than their different backgrounds. It was, BTW a full mass (which half the congregation abstained from), with a Protestant minister doing a few prayers- and everyone was fine with it, even in the older generations of the families.
I can guess at most of my colleagues and friends backgrounds from their names, accents or schools, or clues like seeing photos of their recent trip to Lourdes on their Facebook account, but it isn’t something that comes up or affects our work or personal relationships.