Normally socialists would welcome a republican demonstration against the British monarchy. When the protests against the Queen's visit to Dublin are led by groups such as Republican Sinn Fein, the 1986 split off linked to the Continuity IRA, more needs to be said though.
The Queen's visit sums up a number of things.
At one level, the mere possibilty of a visit by the (unelected) British head of state to the Republic of Ireland reflects the Good Friday Agreement "peace process" in the North. To some extent, it also flows from the myriad connections between Britain and Ireland both in the past (the tens of thousands of Irishmen, Protestant and Catholic, who died in the trenches in British uniform in World War I for instance) and now: economic ties as fellow members of the European Union, the vast number of Irish migrant workers and their descendants in Britain and - not unimportantly for Elizabeth - a shared interest in horseracing.
The protests themselves were small and politically confused. The main slogan on the placards was "Britain out of Ireland". As a BBC commentator pointed out, twenty years ago that would have read "Troops Out" but with British troops in the North largely redeployed elsewhere over the last decade (many of them to Iraq and then Afghanistan), that has clearly lost its grip. The inescapable logic of the slogan is British (i.e. Northern Irish Protestant) people out of Ireland.
Many aspects of the visit were however incongruous, especially the visit to the Garden of Remembrance in Parnell Square. Opened by Éamon De Valera in 1966 on the fiftieth anniversary of the 1916 Easter Rising, it is dedicated to the Irishmen and Irishwomen who fought for independence from Britain over the centuries, from Wolfe Tone's United Irishmen in 1798 to the rebels of Easter week 1916. Given Queen Elizabeth is the granddaughter of George V whose army fought against and ultimately executed the leaders of the Easter Rising, the sight of her laying a wreath there was particularly strange, especially to the strains of The Soldier's Song, the Irish national anthem written by a Republican volunteer in 1916 (and uncle of writers Brendan and Dominic Behan) Peadar Kearney.
It neatly summed up the craven trajectory of the Irish bourgeoisie: from the leaders of the Irish Free State (albeit with British guns in the Civil War) taking advantage, as Michael Collins put it, of "the freedom to win freedom", through the constitutional Republicans of Fianna Fail under De Valera in the 1930's making Ireland a "republic externally associated with the British Empire" (underlined by its neutrality in World War II) and the postwar Fine Gael-Labour-Clann na Poblachta coalition in 1949 formally declaring Ireland a republic and breaking the remaining links with the British Crown to the current leaders of Fianna Fail and Fine Gael inviting a British monarch to lay a wreath at a shrine to Irish Republicanism!