Parading this petty insult aimed at one section of the Northern Irish, as the Sinn Fein President did in a Sky News interview last Sunday, is a throwback to darker days.
Northern Ireland is an increasingly successful country in its own right and deserves the respect and recognition of the Republic of Ireland and all its politicians. Gone are the days when the North referred to the South as the Free State, a euphemism in the 1960s for a backward priest-ridden potato republic.
When, and if, the people of Northern Ireland decide to change its constitutional status then it should be the enthusiastic choice of one proud successful nation voluntarily merging with another proud and successful nation and not an annexation.
Mary Lou is not alone - there are highly sophisticated Irish people, many who have worked for the British, including the UK Government, who cannot resist anticipating the time when they can say ‘we are the masters now.’
But the unionists have to change the tone, too. Clinging to the apron strings of a Tory, Brexit obsessed administration, simply does not serve the nation of Northern Ireland that should be standing on its own two feet.
The prize for NI and by association the whole of Ireland is that it can lay claim a unique standing as an equal partner with the UK and the EU.
It is becoming abundantly clear that UK legislation and sabre-rattling diplomacy, inspired in part by political expediency rather than the good of Northern Ireland, is not going to solve the protocol issues. Nor is lip-licking at the thought of a Border poll.
History demonstrates that when outside or self-interested ambitions meddle in the affairs of the island the result is disastrous.
The time has come for the Northern Irish MLAs, the people elected by the Northern Irish to run Northern Ireland affairs in a Northern Irish administration, to determine the future among themselves.
The UK and the EU are engaged in a dialogue of the deaf. They will open their ears only if Northern Ireland itself screams loudly enough. And that scream must be in unison.
Putting NI parties to the test, preferably with but even without the restoration of the Assembly, to work with each other to recommend changes to the Protocol seems an obvious if challenging approach.
Could London and Brussels, with Dublin’s blessing, bring themselves to bestow this task and bring focus to the currently squabbling parties of NI.
It is, after all, only they and the people they serve that will have to live with the ultimate outcome.
Impressively NI is today the most successful economic part of the UK after London. There is little doubt that the vast majority of both the northern Irish and the Northern Irish are proud of the achievement and would like to move on to even greater things.