Except, by the Palestinian supremacist's argument, Ireland using said weapons to defend herself would be genocide against the British. Ireland has to sit there and take the rocket fire for as long as the British feel like killing Irishmen.
And don't forget, if the British send SAS across from Northern Ireland to murder their civilians, the Irish are not allowed to build a wall. If they build a wall the Brits may dig tunnels underneath to send in SAS troops to kill Irish civilians for the atrocity of building the wall and putting the Brits into an "open air prison". If the Irish ask people not to give the Brits rockets to rain down upon them or armaments for the SAS to use to terrorize them, they're of course racist against the British and it's just one more reason that the Brits are justified in wiping out the Irish.