As a person from Northern Ireland, I'm not sure what holiday you're referring to.
Closest I can think of is the 12th July, which is a holiday, but not one celebrating burning Catholics[0]. You might be referring to the bonfires that are lit on the 11th, but that's not a holiday.
Aside from some small events in Scotland, the 12th July is not celebrated in the rest of the UK.
Is Guy Fawkes Day in November not a big thing in NI? It is in England, at least. Although the traditional burning of the effigy of Catholic dissident/terrorist Guy Fawkes is becoming less common and people just are more commonly just treating it as a general holiday.
No, we don't observe it at all, in either community. Halloween is bigger here, and observed by both main communities, it's probably close enough to 5th November that we've just ended up forgetting about Guy Fawkes.
Plus it's taught in school as an English event, and we have enough of our own history going on in the early 1600s.
It was a terrible tragedy, but it’s patently absurd that we should give someone a jail sentence for making a joke about it.
(The jail sentence was suspended, but that’s hardly the point. Any criminal conviction, even a fine, carries the ultimate threat of jail, or, if you resist arrest, even death — all this, for a joke).
Are you sure you condone joking about the deaths of people in Grenfell Tower?
I've lived on these shores (South Somerset) for 52 years now and I have made the most awful jokes about some things as anyone probably has here. However, there is a point beyond which I won't go - causing deliberate hurt.
I don't know about the particular case that you refer to or actually skirt around - citation needed please.
A joke does not cause hurt beyond a slight nick with a possible small amount of blood loss. Beyond that it is not a joke and is an insult.
I don't condone the actions, but a jail sentence is utterly absurd and is, frankly, very unsettling. Why should insulting people be a jailable offense? There wouldn't be a stand up comedian left walking free if we consistently enforced this.